Lichen communities in the British Isles: A preliminary conspectus

TO 

PETER W. 

IAMES, DAVID 

ANd FRANCIS 

I. 

II. Introduction 

The Phytosociological Approach 

A. Nomenclature 

B. Taxonomy 

III. Epiphytic Communities 

Calicion hyperelli 

Cladonion coniocraeae 

Graphidion suiptae 

Lecanorion subfuscae 

Lecanoion oariae 

Lobarion puhnonariae 

Parmelion laeztigatae 

Parmelion perlatae 

P s eudeoernion furfur ac e ae 

Usneion barbatae 

Xanthorion parietinae 

IV. Limestone Communities 

Aspicilion calca.reae 

Xanthorion parietinae 

V. Other Basic Rock Communities 

VI. Siliceous Rock Communities 

A. Shaded 

Leprarion chlorinae 

Lichen Communities 

in the British Isles: 

A Preliminary 

Conspectus 

L. HAWKSWORTH 

ROSE 

296 

297 

298 

301 

304 

306 

313 

3t4 

318 

3t9 

322 

327 

330 

33+ 

338 

3+2 

349 

349 

360 

361 

354 

36s 

365

296 P. W. Jante"^, D. L. Ilawhsworth and ],'. Rose 

B. Iixposed 

Lecideion tumid.ae 

C. 

D. 

P s eud et e r nio tt. fu r.fitr ac c ae 

Rhi:ocurpion alTirolae . 

LI mbi li c a r io n c y hit d r i c a e 

Nr-rtrient-en riched 

Parmelion conspersae 

X antltorion p ari e t inae 

Nlir.reral-rich . 

A c ar o s p o r t)o n s ino pt| c a e 

E. Marine arrcl Nlaritime Corrrrnunities 

F. Aquatic Comrnur.rities 

\lII. Terricolous (,'ommunities 

A, Pcbbles 

B. Ilasic soils 

C. Coastal soils and dunes 

D. Acid soils and peat 

\rIII. Sun-rnrary 

Note on the Relevi Tables 

Acknorvledgements 

References 

I. Introduction 

370 

370 

371 

372 

374 

3 7rJ 

3 7fl 

3 rJZ 

.r u2 

3li2 

3rJ4 

389 

3 9.1 

3()+ 

l(r- 

400 

+0) 

+07 

40,\ 

408 

40e 

compared with investigations into the systematics and gcograPhicrl 

distribution of lichens r,vithin the British Islcs, the study of thc itrtrctr,r. 

ancl comp

298 P. W. James, D. L. Hazlhswortlt and F. Rose 

cannot be accommodated u'ithin particular units (although the majoritv 

gcnerally can be), and may be intermediatc betu'een one or morc (u'hcthcr 

they arc definccl numerically or by phytosociological methocls). Phytosociology, 

in our opinion, should aim to dctermine those major nocla in the 

continuum of plant communities which arc related to clearly recognizablc 

ecological ancl environmental parametcrs, rather than to fit all stancis 

encountered into a rigid system of too strictly defined associations. In 

most investigations, phytosociologically dcfined noda are derivecl cssentially 

by floristic ancl intuitive methods, but rroda can also be rccognizccl 

as a result of numcrical analyses of data obtained from ranclornizccl sarnpling 

techniques. '1'he relative merits of thcse approaches have alrcacly bcen 

the subject of considerable debate, but only recently has a cornparisorr 

been made between intuitive phytosociological and a number of numcrical 

approaches (Frenkel and Harrison, 1974).'Ihese authors fbund that thc 

intuitive phytosociological method was extremely valuable for the rapicl 

reconnaissance and establishment of basic groupings, particularly in 

terms of the man-hours expended, although a combination of both 

methods was likely to prove more useful than either on its own in thc 

production of an entirely comprehensive system. 

In the case of lichen communities, the dcsign of a randomized sampling 

technique or programme u'hich tvill lead to the detection of the rnajor 

noda presents special problems, mainly unsolved as yet, on account of the 

large number of variables involved alTecting the communities. Iior this 

reason, intuitive methods of sampling are currently the most satisfactorl' 

means of detecting the diversity of the lichen communities in an area. 

A. Nomenclqture* 

Accepting that the subjective, or intuitive, method is a valid one for thc 

recognition of major noda, the question then arises as to u'hether suclr 

noda should be provided u'ith latinized names and ordered in a hierarchical 

system. 'fhe provision of a latinized name enables (or should enable) the 

concept of a particular community to be readily communicated ancl 

names emproyed in this chapter. 

:?,t;: 

ational 

rnomic 

10. Lichen Communities in the British [sles 299 

disctrssecl in the literaturc;for reasons of precision such narnes require 

author citations and rules to control their validity and application. Although 

somcwhat complex systems of rules have been proposed (e.g. 

Meijcr-Drees, 19-53; see Hau,ksworth, 1974), no internationally accepted 

codc comparable to the Intcrnational Code of Botanical Nomenclature is 

cr.rrrcntly available. Thus, cven within Europe, variations in the proceclures 

followed in naming plant communities exist. One of the most 

important of these frorn thc point of view of the stabilization of narnes is 

thc practicc of changing the names of phytosociological units as the names 

of thc species utilized in thosc units are changed; Laundon (1967) did not 

do this, for example, rlhile somc authors have, and yet thcy have left 

author citations for the syntaxon unchanged (e.g. Kalb, 1970; !\;irth, 

1972). Othcr problems arise rvhen authors adopt latinized names based on 

releve c.lata in earlier works where the original authors not only did not 

coin latinized names, but also gave no indication that they considered 

their communities of syntaxonomic value, as in Klement's (1955) treatment 

of Almborn's (1948) "communitics". 

In our view, a closer correspondence between the procedures of syntaxonomy 

and the rules of ic'liotaxonomy (namely the International Code 

of lJotanical Nomenclaturc, Sta{1eu et al., 1972) is requirecl ancl to this end 

,uvc have endeavoured to apply the following criteria in this chapter. In a 

ferv cases (see p. 353) the nomenclatural situations are so complex that 

r,r'e have preferred to follow' continental usage e\/en whcre this is almost 

certainly contrary to the vicws expressed below; it rnay be that a case 

coulcl bc made for the conserva,tion of some extremely well established 

namcs of syntaxa. 

1. Names in all languages are accepted and latinized 1>rooided that their 

authors accorded thern a phytosociological rqnh. T'hus, tables of records to 

shou. taxa associated rvith a species in autecological studies are rejected 

ancl Sl'ntara referred to by their authorS aS t'communities", "noda" etc., 

are omitted unless the original author latinized them (i.e. implied they 

hacl phytosociological rank). Under this rule thc "comrnunities" of 

Almborn (1948) and the "noda" of Rose ancl Jarnes (197+) are thus 

considcrcd invalid. 

2. In cases where courrnunity namcs zol fulfilling criterion (1) above 

have been taken up later and attributed to the earlier author either alone or 

as a "combination", such names are treated as ne\\/ ancl attributed to the 

latcr author alone. 

3. ]r4'here the name of a syntaxon fulfilling criterion (1) and based on 

t$'o or more specific narnes is contracted by a later author, it is treated as a 

nc\\' name and attributcd t

300 P. W. James, D. L. Httwhsworth and F. Rose 10. Lichen Communities t)n the British Isles 

namc. 

a nc\\r syntaxon, being unaware of the existence of an earlier homonyr| 

mtrst clearly be rcjected. "Misapplied" names of syntaxa are not consiclcrct, 

in synony.ries presented here as they can have no nomenclatural sir. 

nificance. 

-5. \\'ith resp tive data a mes of associu 

tions, subassoci acceptable (1), where s.cl 

narnes a.re "no lack anv to the specie, 

prcscnt and th they are lid. Such datr 

6. 'l'he correct name for an association is taken to be a combination .l 

the carliest ar'-ailable acceptably published syntaxal epithet, con-rbinecl or 

reco'rbincd whcre necessary, with a name deriv.d f.n- thc mocicrn 

idi.taxonomic gcnus in which that species epithet is currently praccd . 

clranges in species namcs are not follou'ed in syntaxal nalnes hcic. \\'hcr, 

narncs arc reconbined, the author of the recombination is indicated antl 

that of thc basionvm placed in brackets before the later author's nanrc, 

thc same method of citation is followed when there is a change of syntax.nomic 

ranl< even if the actual name is unaltered (as in the cuJe of a transfcr 

fron-L suballiance to alliance). 

Although contrary to proceclures in the International code of lJotanical 

I be noted from the above (criterion 1) that tht, 

practice of accepting names in languages in addition 

ere. Whether it is advisable to continue this may bt: 

301 

dcbatablc, as lrhile devalidation \vould very considcrably reducc the 

nurnber of syntaxal names to be considered by modern syntaxonomists, 

at the same timc it rvould leacl to changes in somc of thc better known and 

u i.lcll' acceptc(l comrnunity namcs. 

In our opinion, the adoption of an internationally agreed set of rulcs of 

phytosociological nomenclature is urgently required, as only through this 

rvill stability ancl consistency in the application of names bc achicrvcd. 

Ideally, this matter should be considered b1' the XlIIth -lnternational 

Botanical Congress to be held in Sydney in 1981. 

B. Taxonorny 

The phytosocioiogical approach, in addition to thc technical norncnclatural 

problcms outlined above, is beset by a numtrer of taxonomic difficulties 

when one considers the application of existrng lichen community nantes: 

1. 'L'lrcre is an ertrcrnelv large number of namcs of lichen commr,rnities 

already publishcd to consiclcr. Dclzenne-van Haluwyn (I976) cornpilcd 

about 1700 but hcr listing is vcry far from complcte an

302 1,. W. -lamcs, I). L. l[azpl

30+ P. W. ./ames, l). L. Hawksworth and tr'. Rose 

discovcry of one or t\\'o spccies either characteristic of or faithful to a 

particular community (e.g. the Lobarion) it is u'ell worth spending further 

time searching for additional members of that community. A knorvledge ol, 

the composition of the various communities described here is consequently 

an aid to the making of comprehensive surveys of the specics 

present in a particular site. 

III. Epiphytic Cornrnunities 

The very large number of factors determining the development of particular 

corticolous and lignicolous assemblages of lichens have been tht' 

subject of detailed reviews by Barkman (1958) and Brodo (1974) whost 

works should be consulted for further information on these aspects 

Amongst the more important of thcse in the British Isles are: (1) degrct 

of illumination; (2) humidity of the environment; (3) age of the barli 

surfacc; (4) degree of corrugation of the bark; (5) degree and rate o1 

sloughing of bark; (6) continuity and age of woodland cover in a particular 

site; (7) inclination of surfaces; (B) aspect; (9) degree of bark leaching br 

rain; (10) degree of impregnation of bark with organic nutrients; (11) air 

pollution; (12) pollution by agricultural chemicals; (13) pH of the barl 

surface; (14) basic nutrient status of bark; (15) presence of tannins 

betulin or resins etc., and (16) moisture-retaining and absorbing propertic, 

of the bark. 

As corticolous comrnunities occur on a living substrate they are par. 

ticularly fluid and this dimension has to be borne in mind in their delimitation 

as transitions between noda will inevitably be of frequent recurrencc 

'Jihe epiphytic lichen communities of the British Isles are arranged herc 

in cleven alliances. These are treated alphabetically, as are the associations 

within thcm, for ease of reference. The main relationships of the alliances 

to each other are summarized in Fig. 1 and the following key illustrates 

the main floristic differcnces between them. 

1. Old forest indicator species (see 'lable II; e.g. Lobaria spp ' 

l{ephroma spp., Pachyphiale cornea, Pannaria spp., Parmelielltt 

spp., Slecla spp. and Thelotrema lepadinum) frequent to abunclant 

old forest indicator ;p;i". ;;;"; ::':i': i:^'."':'::': t.'O, 

2. Crustosclichensdominant .........1 

Iioliose and/orfruticose lichens dominant . '. ' '... ( 

3. Arthoniales, stalked Caliciales, Hysteriales (including Lecanacticiaceac), 

Lepra.ria spp., or pyrenocarpous lichens dominant...... 4 

I,ecanoralesorCltpheliumdominant ......5 

+. 

-5. 

6. 

7. 

8. 

9. 

10. 

10. Lichen Communities in the British. Isle.s 

Arthonioid, lirelliform or pyrenocarpous lichens dominant; cornmunities 

of young twigs or smooth bark often in somcwhat 

shaded situations . . . . Graphiclion sa,iptae (p. 31a). 

Caliciales, Lecanactidaceae, Arthonia impolita or Lepraria spp. 

dominant; communities of dry bark, bark recesses, or quickly 

drying lignum . . Calicion hyperelli (p. 306). 

Lecanora cltlat,otera, L. confusa, L. pallida, Lecidea symmi.cta or 

Lecidella ela.eochroma abundant; pioneer communities of tu'igs 

forming mosaics of small juxtaposed thalli 

. . Lecanorion subfuscae (p. 318). 

Bacidia clt.lorococca, Cyphelium inquinans, Lecan.ora cottizaeoides, 

L. z;aria or Lecidea scalaris abundant to dominant; communities 

not confined to twigs, often in moderatcly polluted areas, often 

rorming extensive 

:::: ':Ti: .^".0 :*":!,il:;:o;-'ili,,,(p. 31e) 

Acrocordia, Anaptychia, Buellia, CaLoplaca, Gyalectina, Physcia, 

Physciopsis, Physconia, Teloschtlstes or Xanthon.zz species, or 

Parmelia acetabulum, P. elegantula, P. laciniatula or P. quercina 

frequent to dominant; communities of nutrient-rich or nutrientenriched 

barks in well lit situations . . Xanthorion parietinae 

(P.3+2)- 

Above genera and specics rare or absent; communities of mainly 

nutrient-poor barks ... .. . 7 

Cladonia species dominant; on bark in humicl situations, rotting 

wood, stumps ancl tree bases . ... Cladonion coniocraeae (p. 313). 

Cladonia species not dominant; communities mainly of well lit 

sites.. ......8 

Ramalina an d/or (t snea species dominant . . LJ sneion ltat b atae (p. 3 3 8). 

Alectctria, Bryoria, Cetraria, Hypogymnia, Parmelia, Parmeliopsis, 

Platismatia or Pseudeteraia species dominant . . . . 9 

Parmelia caperata, P. perlata, P. reticulata, P. reaoluta or P. soredians 

present to dominant or co-dominant; communities of well lit 

moderately acid barks becoming rare in northern Endland and 

Scotland Pat melion perlatae (p. 33U). 

Alectoria, Bryoria, Cetraria, Paymelia laexigata, P" taylorensis, 

Parmeliopsis, Platismatia or Pseudexerzra species dominant . . . . 10 

Parmelia laez;igata, and/or P. taylorensis present; Cetreh)a, Menegazzia, 

Mycoblastus, Ochrolechia or Sphaerophorus species often 

present to abundant; communities of well lit extremely acid 

ieached bark in areas of exceptionally high rainfall . . Parmel,ion 

laeaigatae (p. 327). 

305

30(r P. W. )fames, D.L. llawluzporth and 1". Rose 

Alectoria, Ilryoria, Cetrartla., ITypogymnia, Parmelia sat;a.tilis, 

Pa.rmel)opsis, Platismatia or Pseudeternia species present to 

dominant or co-dominant; communities of acid barks commonest 

in northern and upland arcas of England and central and eastcrr., 

Scotland with lower rainfall . . Pseudexeynion.furfuraceae (p.334). 

c 

.9 

_= 

6 o 

.! 

Frc. 1. Principal relationships 

British Isles. 

All. 1. Calicion hyperelli 

Xonlhonon 

porielinoe 

c o; 

6 d 

: 

Shode ,/ humus / 

epiphytic alliances present in th, 

Calicion lryperetli eern. & Hadad, ht Hada(, Pfiroda 36, 25+ (1944) fnotes onh 

seen] ; type: Lecanactidetum abietinae Hil.-Coniocybion gracilentae I{len. 

Beih. Feddes Repert. 135, 146 (1955).-Leprarion Almb., Bot. Notiser, Suppl 

1 (2). 33 (lt)48).-Calicion otuidis Fal>., Monogr. Bot., l4/arsaw 26,24 (1968) [rr, 

"Hadad em. Barkm."]. 

10. Lichen Communities in the British Isles 

307 

This large and species-diverse alliance is united by a common habitat 

r^ther than its species composition, which varies very greatly from one 

association to another. The alliance is characteristic of agcd dry bark of 

deciduous trees and decorticate wood in well lit situations. The associations 

include many species which are strictly faithful to them; a rather unusual 

situation for epiphytic lichen communities. Many occur in ecological 

niches where they either never receive direct rain (i.e. are entirely dependent 

on atmospheric humidity for their moisture) or are in very exposed sites 

where thcir substrates dry out very rapidly follorrying rain. 

Arthonietum impolitae Almb. 

Bot. Notiser, Su1>pl. t (2), 33 (1948).-Impolitetum, .!rlrr'b., K. saensha Vetensh- 

Ahad. Aah. natursk. 11,27 (1955). 

This markedly xerophilous community was treated by Barkman (1958) 

in a rather broader sense than is adopted here (see p. 309). We take it up 

for Arthonia impolita dominated communities on dry, well lit, often 

somewhat basic, barked trees in southern England. The association is 

rather poor in species but Schismatomma. decolorans is a particularly 

common component of it. This association is not infrequent on trees in 

pastures u,here Buellia cenescens, B. punctata, Catillaria grffithii and 

Lecanora expallens may enter into it. 

C alicietum abi etini Kalb 

Hoppea lDenhschr. Regen. bot. Ges.l26,104 (1966). 

This association, charactcrized by stands of Calicium glaucellum, or rarely 

C. abietinum, is optimally developed on decorticate pine wood in the 

Scottish Highlands when additional membcrs of the Caliciales enter into 

it (..g. Chaenothecabrunneol,a) but is also encountered occasionallythroughout 

the British Isles in this habitat and also on the exposed wood of a wide 

range of deciduous trees and, more rarely, fence-posts. Chaenotheca 

trichialis is also a locally important component of this association, but can 

also occur in a {acies of the Calicietum hyperelli (see belorv). Many distinct 

noda may perhaps be recognized within the Calicietum abietini in the 

Scottish I{ighlands but these are too poorly understood at the present 

time to describe here. 

C alic ietum hyp er el li Hil. 

Spisy Piirod. Fac. Karl. Llnio. 41,98 (1925) [as "Associatron i Calicium hyperelum" 

(sic)].-Chaenothecetum. melanophaeae Barkm., Phytos. Ecol. Crypt. Ep., 

3s6 (1es8).

308 P. W. James, D- L. Ilawkszporth and F. Rose 

This association rvas described by Hilitzer (1925) for cornmunitics don.ri 

natecl by calicium ztiride and in u-hich r,ecanactis altietirm was oftcn , 

major component. In the .British Isles this generally spccies-poor assr.,ciir 

tion occurs on dry, rough or moderatcly smooth (e.g. Acer) bark or clrci 

duous trees in lowland areas (most frequently in those subjccted to moclcral, 

air pollution) and also on coniferous trees in central and castern Scotlantl 

communities dominated by Lecanactis abietina appear clistinct frorn tl r 

cali.cietum hy1>erelli in the British Isles and that specics is rarely a n'rajt, 

componcnt of this association here. Lecanctra expallens, Lecidea scaluri 

Lepraria incana., sometimes Buellia schaereri (central and eastern Scotlancl 

Catillaria grffithii and schismatomma decolorans, entcr this associati. 

but it most commonly consists of almost pure stands of calicium salicintrti 

C. ztiride, Chaenotheca ferruginea and Le.praria candelaris. Chaerufilrct 

ferruginea predorninates in polluted areas whilst Schismatomma xirghtert, 

occurs in the driest facies ofthis association. 

ln lovvland Britain the Calicietttm hyperelli is most commonly fountl r, 

the dry (usually north-east) sides of u'ell lit deciduous trees which car.r 

cither the Parmelion perlatae or Xanthorion parietinae on their better- l 

and wetter sides. Allied to this association is a further casily ovcrlookt 

community u'hich may be distinct, which occurs in dry sheltered bar 

crevices of rather basic-barked trecs (e.g. F'raxinus, Salix, (,'lmus) particr 

larly in south-east England and central Scotland. 'I'his community 

dominated by Chaenotheca trichialis togethcr with C. hispidula, C. curtlt, 

siae, C. laeoigata and Cont)ocyhe sulphurea. 

C o ni o c y b e tum furfur ac e a e Kalb 

Ber. bayer. bot. Ges. 41,70 (1969). 

The Coniocybetum,furfuraceae, characterized by abundant Coniot',t'i 

furfuracea, occurs in more shaded sites than the Calicietttm hltperclli al 

when on trees is restricted to basal crevices, exposed roots etc. 'l'lr 

association is not exclusively corticolous ancl also occurs on soft hurrr 

and in rock creviccs where it is protected from direct rain. The Coniot_, 

betum furfuraceae is mainly restricted to rvestern and northern parts of tl 

British Isles, When on rock this association may include elements of tl 

Micnreetum sylxtlcolae (p. 366) and its relationships to that comnrnnir 

nrerit further study. 

Lec anac tidetum abietinae Hrl. 

Spisy Pfirod. Fac- Karl. Unia.4l,9+ (1925) fas "Association i. Leca.nott 

a.bietina."l. 

10. Lichen Communr'.ties in the llritish l.rles 309 

Comrnunities dominated by Lecanactis abietina occur in gencrally sirniLrr 

habitats to the Calicietum hyperelli but favour somcu'hzrt r-r-rore shadcci 

and htrmid situations, for examplc dry, very acid bark of [tinus or Ouercu.r 

within a wood rather than isolatecl trees in pastures. The zrssociation can 

perhaps be viewed as a dry bark counterpart of the Parmelietum laeaigatae. 

Where this association is optimally developed, the L. abietina rvith apothecia, 

Calicium r:iride is often completely absent, ar-rd while Clmenotlteca .ferruginea 

is often to be found in the vicinity, it tends to be on slightly less 

sheltercd parts of the trunks and to represent a fragment of the Calicietum 

hyperelli rather than forming a part of the present association. The 

Lecanactidetmt abietinae is rather poor in specics in thc Ilritish Islcs 

although Lepraria incana and Schismatommtt decolorans nray occur in it 

from time to time. Arthonia leucopellaea, Lecana.ctis amylocea and somctimes 

1,. corticola or L. d.ryophila, are rare members of this association 

occurring in, for example, south-u'estern ancl north-eastcrn Scotland ancl 

the Nerv Forest. In old r,r,oodland areas Schismatomma nioeum is also a 

frequent member of this association. 

Lecanactidetum premneae ass. nov. (Table I, F-ig. 2) 

This very distinctivc association, lhc " Schisma.tontme decolorans-Lecanactis 

premnea--Opegrapha lyncea community" of Rose and Jamcs (1974), 

appears to ultimately become the post-clinlax commur)ity of very ancicnt 

(over 300 years) Ouercu.r trees ancl can cover their entire surfaces both in 

open parklands ancl in forested areas (e.g. thc Ner,v Forcst) in southcrn 

Britain. It colonizcs bark surfaces which have bccome dry and brittle lvith 

age and lost their water-holding capacity but retained a rclativcly high pIJ. 

Though an association clearly relict from ancient forcsts, it does not nccd 

a forest microclimate to survive and can occllr on ancicnt, nou' isolatccl, 

trees. 'Ihe association is unknown in Scotland and appears very rarcly in 

Ireland. 

The characteristic species of the Lecanactidehtm ?remneae are Lecanactis 

premnea, Opegral>ha lyncea, O. prosodea (extreme south of England only), 

Schisnmtotnma decolorans, and sometimcs S. r:irgineum. Arthonia impolita 

and Buellia canescens are sometimes present in pasture sitcs. Although 

almost entirely restricted to agcd Quercus (though also known on agccl 

Fagus), a facies of this association (lacking O. lyncea) occurs on extremcly 

ancient Taxus trees (usually in churchyards). 

This community has been littlc understood in the past, doubtless duc tcr 

tlre scarcity of ancient Quercus trees outsidc the British Isles, but elemcr.rts 

of it wcre includcd by Barkman (1958) in his rather broad concept of the

Tesru I.x 

Lecanactidetum premneae ass. nov. 

Species Stands 

+5 

Arthonia impolita 3.3 

Buellia canescens 

Catillaria grifithii +.2 

Chaenotheca brunneola 

Cladt,nia coniocraea 

C. parasilica 

Ettterographu crassa 

H a em atomme o c hr o leu curn 

var. porphyrium 

Lecanactis abietina 

L, premnea 

Lecanora expallens 

Lecidea granulosa 

L, quernea 

L. uliginosa 

Lepraria candelaris 

- 7.2 

)-) 

t"2 3.3 4.5 3.3 2.3 - 

1,"2 3.3 

+.2 2.3 

- +.2 

- +.2 r.2 

L- incana 

_L, _ 11 

l.a 

2.2 1.2 1.2 

Normandina pulchella - +.2 

Opegrapha lyncea 

O. prosodea 

Parmelia caperata 

P" glabratula 

P- sulcata 

Pert u sar i a h e n i sph aer i ca 

P. hymenea 

Phlyctis argena 

Ramal'ina farinacea 

Rinodina roboris 

Schismatamma decolorans 4.3 3.3 +.1 

Hysterium angustatum 1.1 

Bryum capillare 

Hyfnutn cupressiforme 

I so I heci u m myosuroi d es 

Lo p hocol ea het e rophyl la 

Metzgeria furcata 

Mnium hornum 

Orthodontium lineare 

*See p.408 for notes on relevd tables" 

Ftc. 2. Lecanactidetuln premneae on ciry barh on an ancient oak, Species present 

include: Caliciurn t:iride, Lecanactis premnea (predominating), Lepraria incana, 

Ramalina farinacea and Schismatomma decolorazs (Hampshire: New Forest, 

Vinney Ridge, 1969, P. W. James). 

1. Cumbria, Naworth Park (35/- 6--): old Quercus in pasture, 1'0 m diam, 

incl.90', aspect SW,0'5 x 0'5 m, cover 600/0,31 August 1973, F.R. 

2. Hampshire, New Iiorest, Moyles Court (41/1--0--) : ancient Quercus by road, 

2'5 m diam, incl. 90', aspect N, 1'0 x 0'5 ln, cover 709L,20 September 1967, 

F.R. 

3. Hampshire, New Forest, Eyeworth Wood (41/2 -- 1--): Quercus robur, 

0'6 m diam, incl. 90", aspect E, 1 0 r 0'5 m, cover 9O()i), 25 June 1968, F.R. 

and J. J. Rarhman. 

4. Kent,LullingstoncPark(51/5--6--):ancientQuercusinrelictvalleyforest, 

1'6 m diam, incl.90', aspect S, 1'0 x 1'0 m, cover 6096, 10 January 1969, F.R. 

5. Norfolk, Merton Park, Merton Oaks Wood (5219 - - 9 --): ancient Quercus 

in wood, 3'0 m diam, incl. 90', aspect S, 1 0 r 1'0 m, coYer 70()6, 5 June 1970, 

F.R.; type record. 

6. Norfolk, I{imberley Park (63/0 - - 0 - -): ancient Quercus by drive in parkland, 

2'0 rn diarn, incl.90', aspect S, 1'0 x 1'0 m, cover not determined, 8 March 

1969, F.R. 

7. Sussex, Parham Parh (51/0 --1- -): very old Quercus in park, 1'5 m diam, 

incl.90', aspect N, 1'0 x 0'5 m, cover 909'o, 5 Novernber 1968' F.R. 

B. Wiltshire, Longleat Park (31/8 --4 - -): ancient Quercus in open parhland, 

,.1 1.1 diarn, incl. 90', aspect S, 1'0 x 'l'0 m, cover TOoA' 5.June 1970, F'R.

312 P. W. James, D. L. Hawksztorth and F. Rose 

Artlrcnietum impolitae treated above. It certainly occurs in Francc in tirc 

F6rct de Fontainebleau and Brittany. 

Leprarietum candelaris (Matt.) Barkm. 

Phytos. Ecol. crypt. Ep., 355 (1958).-Lestraria candelarr-s Gesellschaft N,Iatt.. 

Ber. West-preuss" bot.-zool. Ver. 59, 16 (1937)" 

'lhe Leprarietum candelarzl is dominant on the dry north and east sicles o1, 

hardwood trees in forests in relatively unpolluted parts of the British Islcs 

where the rainfall is rather low (particularly in north-east scotland near the 

Moray Firth). Elsewhere in southern and eastern England it is largeh, 

confined to dry bark crevices, where it is often associated with Schismatonrma 

decolorans, although it does occasronally sprcad from crevices to fulh' 

exposed, raised flattened bark surfaces in a few lotv-rainfall southcrn 

areas (e.g. extreme south Devonshire). 

The Leprarietum candelarzs is closely related to the calicietum hy'perel.li 

and appears to be a more lowland countcrpart of it in the British Isles. 

Leprarietum 'incanae ass. nov" prov. 

l'his association has a similar ecological amplitude to the coniocybetunr 

.furfuraceae occurring not only on the shadecl parts of trees but also o' 

humrrs, on dry porvdery soil in rock crer.ices and on rock. Lepraria incanu 

often occurs in almost purc stands l>ut cladonia coniocraea, Lecideu 

granulosa and L. uliginosa frcquently cnter into the association on trees. 

a'he Leprarietum incanae is the most shade and air-pollution tolerant of tht 

associations of the Calicion hyperelli treated here extending far into urban 

areas in cracks of the bark on the basal parts of deciduous trecs. 

O p egr aphe tum fus c e ll ae Almb. 

Bot. Notiser, Suppl. I (2), 140 (1948). F'uscelletmn Almb., K. sxenska Vetensh- 

Akad. At:h. natursk.lf , 37 (1955). 

A rather specics-poor community dominated by opegrapha xernicelliJert, 

occurring mainly in woodlands on dry bark of deciduous trees but somctimes 

spreading on to adjacent Hedera stems or siliceous rocks. Aclditional 

important components include O. ochrctcheila, O. z;ulgata and Pyrenulu 

nitida. This association occurs on a wide range of deciduous trees, al, 

though also knorn'n from conifers, but in Britain prefers somewhat bascrich 

barks. Interestingly, like the Parmelietum reLôlutae (see p. 331) it is 

found on conifers only in areas where there is little or no air pollution 

10. Lichen Communities in the British Isles 313 

Two facies of this community can bc recognized in the British Isles: (1) 

the typical nodum on shaded basic barks (.e.g. Lllmus) with Opegrapha 

t:ernricellifera, O. ochrocheila and O. lichenoides, and (2) onc on shaded 

more acid barks (e.g. Fagus) where O. niveoatra predominates and Pertusaria 

leioplaca and Graphis species are characteristically present. The 

Opegraphetum fuscellae, as conceived here, has a rather southern and 

western distribution in the British Isles. 

Lll. 2. Clq.donion coniocraeae 

Cladonion coniocraeae Dr,rvign., Bull. Soc. r. bot. Belg. 74, +9 (1942); type: 

C ladonietum conio cr ae ae Duvign. 

This alliance was first describcd from Belgium for communities dominated 

by Cladonia coniocraea and applicd to British communities by Laundon 

(1956, 1958, 1967) and later authors. 'l'wo associations are recognized in 

Britain both of r,vhich can occur on tree bases ancl peaty soils. 

C ladonietum c enote ae F r ey 

Verdff . Geobot. Inst. Rubel 4,2+9 (1927). 

This association, first described from Scandinavia, is used here in its 

original somewhat restricted sense (see below) for the Cladonia-rich 

communities which are found on very dry and acidic tree bases, dead 

stumps and on peaty soil under mature native pine woods in the Scottish 

I{ighlands. It is particularly well developed in the Glen More and 

Rothiemurchus Forests where it includes as its characteristic species the 

rare or local C. botrytes, C. carneola, C. cenotea, C. defctrniis and C. nemoxyna 

as well as the more widespread C. furcata, C. gonecha, C" gracilis, C. 

scabriuscula and other moorland Cladoniae. 

C ladonietum c oniocr ae ae D uvign. 

Bull. Soc. r. bot. Belg.74, +9 (19+2). 

\-he Cladonietum coniocraeae is a well marked community which is both 

pollution tolerant in the British Isles and has a wide ecological amplitude, 

occurring on the bases of shaded trees (sometimes extending far up the 

trunks in ravine-like sites), rotting wood, clayey and pcaty soils, and 

siliceous rocks in damp situations. The community, when optimally 

developed, is rich in species of Cladonia, although C. coniocraea is the most 

important; others commonly encountered include C. chlorophaea, C' 

digitata, C. fmbriata, C. macilen.ta, C.'pyxidata. s. str. and C. squamosa" An

Species 

C an del ariel I a oit e llina 

Catillaria grffithii 

Ezternia. prunastri 

Hypogymnia physodes 

Lecanora chlarotera 

L. conizaeoides 

L. expallens 

Lecidea quernea 

Lecidella elaeochrotna 


L. incana 

Ochrolechia yasudae 


P. glabratula 

P. perlala 

P. reticulata 

P. reooluta 

P. saxatih)s 

P, soredians 

P. subrudecta 

P. sulcata 

Pertusaria albescens 

var. corallina 

It. amara 

P. pertusa 


Ramalina farinacea 

R. fastigiata 

Hysteriam angustatunt 

Tesrn IV. 

P arme lietum r et olut ae Klern. 

L1 

C oI olej eu n e a minutis simus 

Fnillania dilatata 

Hypnumutpressiforme 7.2 

Metzgeria furcala 

M. frutirulosa - 

Ulota phyllantha 

Zygodon oiridissim.us 

2.3 1.2 1.3 

+.2 7.2 2.3 

3.4 

_ _L1 _ 

| .P 

- 7.2 1.3 

J.J - I.J 

- 7.2 

- 3.2 2.3 

1.3 

1.2 1.3 

7.2 

- 

+.0 2.2 +.0 

Stands 

45 

2.3 

3.2 

J..J 

1.3 

1.3 

+.1 

3.2 

1., 

T.L 

_J- 1 

1.2 1.2 1.2 2.2 

+.1 - 2.2 7.2 

L', -L) 11 

l.a 1.4 

_ r) 'lI 

I'a 

+.3 3.3 

- +.0 - 1.2 

1.2 

- +.0 

2.2 - 2.+ 

1.2 2.3 1.+ t.2 

_ r2 12 _ 

l'/ 

11 

_ 2.3 

- )) 1? r0 I' 

- +.3 7.2 +.0 

3.2 1.3 +.2 

7.2 2.3 

_ i.3 

1.1 +.0 +.2 +.0 

- +.0 

- +'0 

1.3 

tj 

1.3 

1.2 

+.3 

1.2 

+.0 

2.2 

),) 

10. Lichen Communities in the British Isles J.' J 

western Scotland north to Skye and Applecross, and parts of Angus, Fife 

rainfall upland areas the Parmelietum reoolutqe gives way to the Parmelietum 

laeaigatae. 

The associaiion similarly gives way to the Pseudeaernietum furfuraceae 

in northern continental areas (e.g. Denmark, north Germany), but is very 

1. Cumbria, Borrowdale, Manesty Park(3512-- 1- -): Quercus at edge of wood' 

0'8 m diarn, incl. 90', aspect SW, 0'5 x 0'5 m, cover 75%, 4 June 1969, F'R'' 

D.L.H. and B.J.C. 

2. E. Kent, Hothfield Park (51/9 --+--): old Quercus,l0 m diam, incl' 90o' 

asp. S, 1 0 X 1'0 m, cov , F'R' 

3 . E.' Kent, near Ashford, 

(61 lO - - 4 - -) : Quercus in open 

pasture, 1'0 m diam, incl. 1'0 m, cover 70o/o,24 September' 

P.w.J.

314 P. W. James, D. L. Hawkszoorth and F. Rose 

dry dccorticate wood C. coniocraea rnay be almost entirely replaced by 

C. parasitica, and in damp woods i'the south and south-west, the rather 

rare c. caespiticia also cntcrs into the association. The most pollutiontolerant 

facies of this community, however, merely compriscs swards of 

c. coniocraea andlor c. macilenta. The association intergrades with othcr 

noda containing species such as Lecidea granrtlosa, L. uliginosa, Micar.ea 

prasirttt, Peltigera canina, P. polydactyla, P. praetextata and Sphaerophonts 

globosus. Bryophytes are important components in this community, the 

introduced Orthodontium lineare (see Rose and Wallace, 1974) bcing 

particularly characteristic in the south-eastern and Midland counties. In 

relatively rrnpolluted areas (lsnea-rich facies occur in better lit sites but 

these, follorving Barkman (1958), are placed in the Cladonieto (.isneettLm 

tnberculatae here (see p. 338). 

The Cladonietum coniocraeae has been treated as a synonym of the 

Cladonietum cenoteae by a number of lichen phytosociologists (e.g. 

Wilmanns, 1966) follorving Klement (1955), but this vierv was rejectecl 

for the llritish Isles by Hawksworth (1972a);from the information provided 

above it will be evident that these two associations differ fundamentally 

in species composition, habitat and distribution and thus clearlv 

merit treatment as distinct associations. 

\rarious infrassociational taxa have been described vvithin this association 

(..g. var. macrocladonietum digitatae Duvign., yar. microcla.donietrnrt 

coniocraeae Duvign., var. sphaerophoretum globosae Duvign., subass. 

cladonietum digitatae Klem.) and while most can be recognized within thc 

Ilritish Isles they appear to be of minor synsystematic value. 

All. 3. Graphidion scriptae 

Gral>ht)dion scriptae Ochsn., Jahrb. St. Gall. naturw. Ges.63,49 (1928); type: 

Pyrenuletum nitidae Htl.-Graphidioz Almb., K. svensha VetenshAhad. Azth. 

natursk. 11, 21 (1955); type: Nitidetum Llmb. 

This particularly r,vell marked alliance is characteristic of smooth bark, 

usually on young trees, branches or twigs, and comprises two distinct 

elements, (1) the pioneer community of trees, and (2) some communities 

persisting on mature trees lvith smooth bark or restricted to deep shade. 

The ()rapltidion scrilttae is characterized by a wide range of crustose 

specics and where macrolichens are encountered within its associations 

they can be viewed as pioneers of subsequent successional stages. Most of 

the crustose species involved are esorediate with either lirellate or pyrenocarpous 

ascocarps. 

The alliance is entirely restricted to the bark of deciduous trees in the 

Btitish Isles. While it evidently merits subdivision into several associations, 

10. Lichen Comnnnities in tlte British Isles 31--c 

few studies have been made on this alliance in llritain so far and the 

following treatment is conseyrenia fallax, A. punctiformis, Dermatina quercus 

(second or third year oak twigs), O1>egrapha atra, Stenocybe pullatula 

(confined to Alnus tv,'igs) and Tomasellia gelatinosa (mainly on Corylus). 

The age of the trvigs and the degrecs of preliminarl' scarring influence the 

intrusion of additional hypophloeodal species which first appear arottncl 

leaf and girdle scars. Lecanora carpinea, L. chla.rotera, L. cottJusa, Lecidea 

symmicta, Lecidella elaeochrome and Rinodin.a sophodes indicate transitions

316 P. ILt. James, D. L" Hawhsworth and F. Rose 

to tl.re Lecanoretum subfuscae, whirst in more pollutcd areas Bacidia 

chlorococca and I'ecanot'a conizaeoidas indicate transîtions to the Bacideet,nt 

chlorococcae and f,ecanoretum pityr 

dominated by Porina chlorotica var 

and O. z'ulgata and little or no Ar 

tinctive; this frequently includes 

(u,ell lit sites) or Pyrenuletum nitidae 

to those associations. 

Gr ap lidetum s cr ip t ae Hil. 

. Karl. LInin. 41,90 (lgZS) [as ,,Associat ion i Gral>his scripra,,l. 

latycarpa.e var. Kraphinetum anguinae D. I{awksw., Ftd stui. 

This name is taken up here for communities of moderatery shaded smooth 

ociation. In its well developecl 

; only G. scripta of the spccies 

inental areas of Europe. 

Forest and south_west Ireland, a 

specics-rich variant of this association occurs r,vhich includcs Arthonia 

stellaris, Arthothelium ilicinunt, Mycoporelrum sparseilum and stenocybe 

septata, together with much Thelotrema lepadinum. 

Although 

_ Ilarkman (1958) subsumed Hilitr.r'. association within the 

P-vrerurletumnitidae, I{ilitzer appears to have recognized the clistinctness of 

these noda and thus his name is adopted. here. 

Pertusarietum arnar ae Hil. 

amara"f . 

1955) [as 

tum Almb., K. svettska ,rrr:r12;::. 

f'his association was useri rather restricted sense 

but has been subsequently Fabisewski (196g) u,ho 

recognized three variants. e is interpreted here as 

comprising somewhat shade-tolerant communities, often on rather less 

smooth bark, in which species of perhtsariapredominate. The community 

10. Lichen Communities in the British Isles 3t7 

is particularly w'ell dcveloped on F'agus in the Ner'v Iiorest and Carpiruts in 

south-east England. Pertusaria hymenea and P. pertusa are the most important 

components although other species of thc genus provide high cover 

values locally (..g. P. hemisphaerica, P. leioplaca). h old forests Haematommtt 

elatinum, Lecitlea cinnabarina and Thelotrema lepadinurz also enter 

into it and the lirclliform species generally present (other than Graphis 

elegans) become replaced by verrucose-fertile and verrucose-sorcdiate 

taxa (characterized by Pertrcaria). 

'Ihe Pettusarietum amarae shows some tendency to intergratlc rvith the 

Pyrenuletum nitidae and could be vierved alternatively as an extrcme facies 

of that association. 

Pgr enuletum nitidae Hrl. 

Spisy Pfirod. Fac. Karl. Unia. 4I,91 (1925) fas "Association b, Pyrenula nitida;'1. 

-Lecanoretun glabratae Klen., Beih. Feddes Repert. 135, 132 (1955) fas "Almborn 

194t3"]. It'litidetum Almb., K. sxensha l'etenskAhad. Azth. natursk. ll,2l 

(1955). Porinetum carfineae Barkm., Phytos. Ilcol. Crypt. lip., 382 (1958) fas 

"noa, ass. prozt,"l, 

The Pyrenu.letttm nitidae, principally characterized by extensive rnosaics of 

Enterographa crassa andior Pyrenula nitida and P. nitidclla, occurs on a 

wide range of smooth-barked deciduous trees when growing in cleep 

shade. Many species may accompany it, of \\'hich Arthonia lurida, A. 

radiata, A. spadicea, A. tumidula, Graphis scripta, Opegrapha atra, O" 

t;iridis, O.'"-ulgata, Pertusaria leioplaca and Phaeographis dendritica merit 

particular note; some of these species may be \/ery important components 

of this association locally. Further east in Europe (e.g. eastern Denmark) 

this association is important on tr-agus in old dry forests ; O1>egraplta z:iridis 

rrsually occurs in such sites but Enterographa crassa is normally abscnt. 

Accorcling to Barkman (1958) the Opegral>lrctrLm herpelrcae Almb. (s1'n. 

Rufescenteturz Almb.) is closelv allied to the Pyrerutletum nitidae. Wliile the 

components of this association occur in the British Isles thev do not 

appear to constitute a well defined associatiolr here; Opegrapha mr.fescens, 

for exam':lc, is essentiallv a species of aged dry bark underhangs of 

F-raxinus, more rarely Quercus, and is perhaps better placed u'ith other 

associations characteristic of this habitat (see pp. 308-309). 'lhe Arthonietum 

htridae l{alb, described from Germany, seems only doubtfully distinct 

from our concept of the Pyrenuletum nitidae. 'lhe Porinetum carpineae 

of Barkrnarr (1958) appears to bc merely an earlr,. stage of the P1'renuletutn 

nt)tidae and so is not recognizcd separately here; this facies, not usually 

found on young tr.vigs, inch-rdes Microthelia micula, Porina cltlorotica var. 

carpinea and P" leptalelt,

318 P. W. James, D. L. Hawksworth and tr'. Rose 10. Lichen Communities in the British Isles 319 

AlI. 4. Lecanorion subfuscae 

Lecanoyio Gall. naturzo. Ges. 63,50 (192g); type: 

Leca nore ! 

Ep., 3eo ";;:Ht"',,::;*;'J:,f;t:gr#:,i":, 

Laund., Lond" Nat.37,72 (1958) fas nom. noa. for "Lecanoretum subfuscae 

Ochsn. p.p."]. 

The nomenclature of this alliance is extremely complex. Barkman (19-5g) 

rejected ochsner's name as highly ambiguous beca..,se of the confirsion 

which surrounds the name Lecanora suhfusca but, as is the case with the 

(Jsneion barbatae discussed below (p. 338), since there can be little cloubt 

that the composition of the alliancc corresponds to Barkm an,s Lecanorion 

carpineae, Barkman's. terminology is rejected here as it has been by, for 

example, Kalb (1970) and Hawksworth (1972). For further information 

on the nomenclature of this alliance, I{alb's (1970) detailed cliscussion 

should be consulted. 

The Lecanorion suhfuscae is essentially a pioneer community of vtell lit 

twigs-and -young trees characterizedby .pecies of Lecanora (particurarly 

the ,r- ' sybfusca species complex) and other hyperphloeociar crrrstos" 

species forming intricate mosaics. A single ,..o.iniion is recog'ized 

within it in the British Isles. 

Le c anor etum subfus c a e HiL 

spisy Pfirod. Fac. Karl. (Jnizt.4!,8+ (lgzs) fas "Associationh. Lecanora sub- 

fttsc a"f .-Lecideelo par as emo-Phly ctideetum Htl-., spisy piirod. F ac. Karl. u nizt. 

41, 89 (7925) fas "Association ir Lecidea paraserni et phlyctis,'1. Lecanoretum. 

allophanae Duvign., Bull. soc. r. bot. Berg. 74, 39 (lg+zi lns :'no*. noz.t.',1.- 

Lecanoretum carpineae atlanticum Barkm., phytos. niot iryl>t. 8p.,392 (195g). 

This association, which is u'idespread through the British Isles, is particularly 

rich in species, the most important components beirg Lecaiora 

chlarotera, L. chlorona, L. pattida and Lecitlella elieochoma. otiler species 

frequently present include Arthonia radiata, Buellia griseo,irens, Graphis 

scripta, Lecanora carpinea, L. confusa, L. expallens, L.-intumesceni, Lecidea 

qtmmicta, opegrapha atra, Parmelia exasperata, p. nrbaurifera, pertusaria 

leioplaca, Pllyctis argena, and Rinodina soprtodes, together *ith'tn. mosses 

Lllota bruchii (near the coast) and u. ph1,ilantha. In slightly more shaclecl 

situations catillaria lightfootii, Haematomma elatinuml Le'canrra jamesii, 

Lecidea tenebricosa and Phlyctis agelaea enter into the association in the 

south and west. In southern Britain the association eventually gives .w,ay 

to the Parmelietum rexolwtae on dcciduous trees as the maciolichens in 

that association tend to grow over the mosaics of crustose species characteristic 

of the Lecanoretum subfuscae. With increasing shade, in contrast, 

the Lecanoretum wbfuscae merges into the Graphidetum scriptae to such an 

extent that stands which are difficult to assign conclusively to one or the 

other association are not uncommon. On Prunus spinosa and Salix repens 

in some coastal situations (e.g. Dungeness, Kent and Berry Head, South 

Devonshire), however, the association includes Lecanora chlaratera, L. 

confusa, Lecidea symmicta and Lecidella elaeochroma but is atypical in an 

abundance of Caloplaca cerina; this distinctive facies also occasionally 

includes Ramalina baltica indicating an affinity with the Ramalinetum 

fastigiatae. 

Several allied associations may well occur in other parts of Europe but 

are in need of further investigation as Barkman's (1958) treatment of them 

is evidently unsatisfactory. The Lecanoretum laez:is Barkm., in which 

Lecanora chlarotet'a is replaced by L. laez,is and Lecidella elaeochroma 

replaced by Lecidea euphorea, is certainly distinct being characteristic of 

warmer areas and starting to appear in southern France; the Lecanoretum 

laexis is also a pioneer twig community and has a wide geographical range 

extending into, for example, the forests of the Azores and West Pakistan. 

Particularly in the more southerly parts of Europe (e.g. southern and 

western France), Teloschistes chrysophthalmxts, T. faxicans and (Jsnea 

fammea appear to enter into communities which might be considered a 

re gional variant of the L e c anor e tum s ubfu s c ae. 

All. 5. Lecanorion aariae 

Lecanorion tariae Barkm., Phytos. Ecol. Crypt" Ep.,362 (1958); type: Psoretum 

ostreatae Hil.--Conizaeoidion Laund., in Kettering and District Field Club, 

First Fifty Years,92 (1956) lnom. illegit.l 

This alliance is employed here for four associations, three of which are 

particularly tolerant of sulphur dioxide air pollution. These do not appear 

to be merely species-poor facies of other more pollution-sensitive assemblages 

of species as they occur from time to time in relatively unpolluted 

parts of the British Isles, particularly on lignun and the acid bark of 

coniferous trees. 

The name of this alliance is nrisleading as it was based on the assumption 

that Lecanora conizaeoides (syn. L. pityrea) was simply a form of L. aaria. 

Despite some recent Czechoslovakian studies implying the contrary (for 

details see Hawksworth, 1973b), thrs conclusion is taxonomically unacceptable 

as these taxa differ chemically, morphologically and in their 

respective distributions.

320 P. l4/. James, D. L. Hau:hsztorth antl F. Ro"-e 

, The Caloplacetum phroginae, placed in this ailiance lvith some hesitation 

by l3arkman (1958), is subsumcd under the physcietum ascendentis of the 

Xanthorion here (see p. 344). 

B acidietum chlorococc ae LeBlanc 

9:,. ,7. Bot. 4r,615 (1963) [as "tJnion h, Bacit]ia chrorococca"l.-I{arb, IToppea 

lDenhschr. Re_gensb. bot. Ges.]26, 110 (1966) fas ,,ass. nozt.,,l. 

occur. 

C y p lt e I i e t um inquin anti s Kalb 

Diss. Bot., Lehre 9, 34 (1970) [as,,Cyphelium,,]. 


It is possible that the very rare eastern Cyphelium notarisii communities 

in Britain are a facies of this association (or perhaps the little understood 

Cyphelietum tigillaris I(lem.) but too few data are available to make any 

reliable assessment as to their syntaxonomic status in Britain at the present 

time. As an example of the composition of this facies the following releve 

may be cited:. Cy1>helium notarisi; (2.3), C. inquinans (2.3), Lecanora 

conizaeoides (2.3), L. oaria (1.3), Ramal'ina fastigiata (1.2) and Xanthoria 

polycarpa (2.2) lE. Sussex, Winchelsea Beach, Rye Harbour (51/9- - 1 - -) ' 

wooden post 250 m from the sea, incl. 90', aspect 225", 0'2 x 0'2 m, 17 

April 1976, F.R.l. 

Lec anor etum pityr e ae Barkm. 

Phytos. Ecol. Crypt. Ep., 363 (1958). 

This is an extremely uniform association which characteristically includes 

only a single species, Lecanora conizaeoides, forming extensive pure 

continuous swards on well lit deciduous trees which can cover them from 

base to uppermost twigs. It is, however, optimally developed only where 

mean winter sulphur dioxide levels are in the range 55-150 pg --t, 

and in this range commonly also occurs on sandstones (particularly in the 

southern Pennines) and peaty moorland soils. Where air pollution levels 

are in the lower part of this range the association is also occasionally found 

on coniferous trees. 'Ihe Lecanoretum pityreae appe^rs to be pollution 

tolerant or a pollution exploiter rather than one needing pollution to 

survive as it does occur in parts of Britain almost entirely free of any air 

pollution; interestingly, in such areas it is almost entirely restricted to 

decorticate wood (especially fence-posts) and either twigs or acid-barked 

trees (e.g. birch and coniferous trees) and usually found in sites frequented 

by visitors from parts of the country where it is common. The association 

appears to have poor competitive ability where there is little air pollution 

and fails to encroach on communities already established. 

'lhe Lecanoretum pityreaa is the commonest or only association on trees 

over large tracts of the British Isles extending northwards from the Thames 

valley, through the Midlands, and into northern Lancashire in the west 

and Northumberland in the east. More detailed information as to the 

behaviour of Lecantra conizaeoides in Britain is included in Hawkslvorth 

et al. (1973, t974). In damper sites, the association frequently intergrades 

with the Bacidietum chlorococcae on twigs, Calluna stems etc. 

Feu' other species ever form important components of this association. 

The most frequently encountered is perhaps Lepraria incana, especially 

in bark crevices or near the bases of trees, although plants of Hypogymnia

322 P. W. James, D. L. Ilawhsworth and F. Rose 

ambigua, for examplc, start to 

he lower end o{ its sulphur 

latter plants represent inter_ 

of the Psea 

bark is nu 

particularly by soot, Desmococcus enters into ' 

-rhe Lecanoretum pityreae is often tacked by Atheria arachnoidea (Berk.j 

Jtil. which can form large pale lesions in it. 

Lecideetum ostreatae (Hil.) comb. nov. 

Psoretum ostreatae Hil., sp^y pfirott. Fac. Karr. Llnht.4l,gg (lgzs)[as .,Association 

d Psora ostreata"f.-Lecidceturn ostreatae schulz 1s"n.,u-rtorth], Beih. 

leddes Refert. 67, +8 (1931) las ,,Lecidea ostreata_Ass.,,j._Lecideion ortreata, 

!3"".{,, in_Kettering and Disirict Field Club, First Fifty years,94 (1956) [as 

"Lecidion"l.-Lecideetum scalaris Kalb, 1)zss. Bot., Lrh* g, '37 (1970) [as 

"Hilitzer 7925"1. 

This air pollution-tolerant association is mainly confined (in moderately 

polluted areas) to the bark of deciduous trees in shelterecr, wJll lif .sites, but, 

Iike the Lecanoretum pitl,reae, will also occllr on coniferous trees at rower 

sulphur dioxide levels. Although an essentia 

also occasionally encountered on decorticate 

and tree stumps), sandstones and brick in m 

British IsIes. Lecidea scalaris predominates i 

times the only species present. cradonia coniocreea, c. fimbriata, Lecanore 

conizaeoides and Lecidea granurosa may arso o..rrr'butlenerallf ha'e low. 

cover values. 'rhe Lecideetum ostreaiae also occurs on charred trunks; 

Lecidea scalaris often fruits in this habitat aod. Lecidea friesii ani Toninia 

carodocensis may also be components of this speciali""j fnci... 

All. 6. Loborion pulmonariae 

Lobarion pulmonariae Ocl.rsn., Jahrb. St. Gall. naturw. Ges. 63, 64 (192g); type: 

Lobarietum pulmonariae Hil. [syn. Nephrometum laeoigatae nr.f.rn.j. -- 

'lhe Lobarion pulmonariae (Fig. 3) is composed mainly of large foriose 

lichcns and robust bryophytes ancr'appears io bc the ,atrr."l fore-.st climax 

community on mature harirwood i.... ,uith barks of pH i.-o-o.o i, 

diterranean climates. ft is nou, very 

to the felling and management of 

forms of pollution. In drier areas it 

there is more light, or to the "on.,ofiio*i'.t:ri:::Jt3t,H:T.ix 

10. Lichen Communities in the British Isles J Z.' 

FIc. 3. Lobayion pulmonariae on oak. Predominant species: Lobaria amplissima. 

(with cephalodia) and L. pultnonaria (Argyllshire: Ardnamurchan Peninsula, 

Camasine, 1967, F. Rose). 

Scotland and Brittany it is largely restricted to mature or older tree trunks 

but in these two regions it wlll occur on relatively young trees and even 

old Corylus bushes. In parts of Scotland with high humiditics it is even 

able to colonize planted trees or avenues while elservhere it has acquired 

an essentially relict status; i.e . become confined to primary rvoodland relics 

with old trees. The Lobarion is rarely well developed in coppice s,oodlands 

unless l)umerous old standard trees are present but persists in many sitcs in 

Enp;land on sheltered ancient parkland Fraxiruts, Quercus and (Jlnrus trees. 

In drier areas (e.g. Sussex, north-east England, eastern Scotland) it is 

usually best developed in forest relics in sheltered humid valley floor sitcs 

or on trees close to rivers in gorges. 

Today the alliance is unable to spread in drier districts into rvoodlands 

less than 200 years old unless these adjoin, or have adjoined, ancient 

woocllands from rvhich dispersal could take place when the trees reachcd 

sufficient maturity. The ability to colonize younger trecs and exist in more 

shaded sites in wetter climatic zones may be due to (1) a higher annual 

growth rate (longer growing season) of the macrolichens concerncd in 

the constantly humid environments, and (2) photosynthcsis being able to 

occur for longer periocls in moist conditions and thus compensating for 

lower light intensities.

32+ P. W. James, D. L. Hazuhsworth and F. Rose 

There is little doubt, to judge from riterature sources and field evidence 

from relict sites, that this a[iance was formerry quite g.rr..ul as the 

epiphytic community of the mature trees of lowland and f*.. -orr,u.r. 

forests of wcstern Europe outside areas of intense Mediterrane^r-, ,rr*r''.,. 

drought (even in these areas it does, however, seem to have existed in 

sheltered, locally more humid, sites). In Mediterranean forest areas it is 

alliance. It may 

y u'ell developed 

ges of glades. In 

Lobarion is also 

itands of coniferous trees (particularly 

Abies pectinata which has a less acid and more water- ani nutrientretenti'e 

bark than lo,st o1h9r conifers). Evidence for the fornrer paramount 

importance of the Loburion in the European hardwood forests is 

provided by (1) the large number of species present in it, most of rvhich 

today show-highly disjunct ancr presumably iiagmented iistributions, (2) 

the relatively high consta.r.y of many of theJe species over the whore 

g_eographical range of the-alliance (which is by no .n.u.r, purely oceanic), 

(3) the number of faithfur species it contains (i.e. species'Jf p..."nt i., 

commurrities of this alliance), and (4) its occurrence in forest situations on 

u:ry wide range of 

1 

d.eciduous trecs (only on Arnus which has a very acid 

bark, pH 4.5, is it really rare). 

-.The synsystematics of this alliance are extremely complex. Several 

distinct associations occur within it but the delimitati'n and nomenclature 

of these are currently unclear. As we propose to deal with the Lobarion in 

some detail in a future publication only a brief discussion of the principal 

noda of the alliance seen in Britain is incluc{ed here. Attention is, iruwever, 

drawn to the detailed discussio's of it in the southern Black Forest and 

(1968) and Klement (1965), respectively. 

European nodum of this alliance, termed the 

species,themost.o.,,,u,,,lyBJJl#:,X jtSitJ'ni"T#i::,: jik?HiltTlt 

particular feature of the nodum is the abundance of bryophytes rvhich form 

a substrate on which the macrolichens grow. Even within the western 

European-range of this nodum, many staids attributabre to it lack manlr 

or even all, of the macrolichens characteristic of it as a result of the effects 

of man. Such species-poor communities probabry always o...,.r"d o., 

sere to the full species_rich nodum; 

,1" community and usually come 

II. In many parts of southern 

d Picardy in northern France, the 

ly as this pre-Lobarion nodum, Even 

V 

10. Lichen Contmunities in the British. Isles 

'l'eur.n II. 

Some componen.ts of the Lobarion pulmorariire in the fipi.ca.l zaestern 

European facies of lhe alliance (- Neph.ometum lusitanicae llurkm.). 

Arthonia didyvxadc 

Acrocordia gemmatao " 

Bacidia qffinis" 

B. biatorina" 

B iator e lla o chr ophor a" 

C atilla ria alr opurpur e a" " 

C. sphaeroides" 

Dimerella lutcao" 

Dzternia prunastrib 

Haemalomttta elatinum 

Lecanora quercicolao 

Lecidea cinnabarina 

L eptogimn li clrcnoide sb 

L. tereliuscuhrm 

Li thogr apha dendrogr apha" 

Lobaria amplissima" 

L. laetexirensu 

L. pulmonari.tt" 

L. scrohiculata." 

N e p hr oma laet-tig atum" 

N orm an d ina'1xilch e ll ab " 

O pegr apha sor e diif u' a" " 

P a chy 1> hi ale c orne tto " 

P ann ar i a me di t err a.n e a" 

P. pit1,vs7" 

P. ruhiginosa" 

Parnrclia crinita"" 

P. gltthratulab 

P. red.denda"" 

P. reuolutab" 

P. saxalilisb 

Parrnelie Ll.a a tlan tica 

P. corallinoides aggr." 

P. plumbeao 

Peltigeru collina" 

I>. horizontalis" 

P. praetextatab 

P er ttts a r i.a hem i sp ha er i c a" 

P. hymenea" 

P. pertusa. 

P. z:ela.l.a.o " 

Porina coralloidea" 

P. hihern.i.ca" 

P. leptalea 

Rannlin.a .farinaceab 

Rinodina roborisb 

Sticta limbatao 

S. syloatica" 

Thelol>sis rubella"" 

T helotrem a lepttdinunf 

Rryophytes 

A nti tric h ia cur t i1>end ula" 

C ampt ot hc ciun. s eri.t: eu.n* " 

F'r ul lania fr agi ll.ifa li a" 

I.'. tamartlscib" 

I sothecium my onr oideso c 

N e c ker a cotnp I a.nat ab'' 

N. pumil.ab" 

O r t ho tric hum ly e lliib " 

Plerogonium gracileo 

Zygodo n baun g artnerio " 

: spccies more or less faithful to this nodum. 

- companlon specres occurrrng wrth a high constancy. 

: spccies also of the"pre-Lobarion" pioneer communitv (see p. 324) 

in thc New Forest (see Rosc and Jamcs, 1974) an

326 P. W. James, D. L. Hawksworth and F. Rose 

away from the more humid western and southern counties, the Lobarion 

tends to be relatively species poor. Often only Lobaria pulmonaria (and 

sometimes L. scrobiculafa) represent that genus, Sticta species are usually 

absent, and the cyanophilous species may be represented only by Parmeliella 

plumbea (or Pannaria rubiginosa in north-east Scotland, e.g. Darnarvay 

Forest). The same pattern of impoverishment appears to occur in this 

alliance in the forests of north, central and eastern Europe (e.g. Denmark, 

Poland). 

Conversely, in south-west England, North Wales and, more particularly, 

western Scotland, Brittany and the French Pyrenees, additional species 

absent further east become locally common (e.g. Lopadium pezizoides, 

Parmeliella atlantica, Pseudocyphellaria crocata, P. intricata, Sticta 

canar;ensis (5. dufourii morphotype\, S. fuliginosa; in a few areas of western 

and southern England and Wales, also Rinodina isidioides). An especially 

species-rich facies of this alliance occurs in moist valley-bottom woods in 

sheltered lowland situations in western Scotland, particularly on inclined 

boughs of old Corylus or Salix atrocinerea in wet carr woodland; this 

includes fewer crustose lichens but all four British Lobaria species (all 

fertile in western Scotland; all but L. laeteoirens rarely so elsewhere), 

Pannaria, Parmeliella and Pseudocyphellaria species and, occasionally, also 

Heterodermia obscurata. In such constantly wet conditions Cetreliq 

oliztetorum s.1., Menegazzia terebrata, Parmelia endochlora, P. laez,tigata 

and P. taylorensis (all species usually found only in the Parmelion laeztigatae, 

see p. 327) may also occur, together u,ith Leptogium species (particularly 

L. burgessii), Parmelia sinuosa (on twigs) and Ulota species. This nodum, 

which is very distinctive when well developed, shows affinities with both 

the Parmelion laevigatae (although on far less acid bark) and, through 

Lecanora jamesii communities, to the Graphidion scriptae (generally of 

smooth-barked twigs and small branches). In such sites in western 

Scotland and south-west Ireland, small twigs and branches often support 

Graphidion with Lecanactis homalotropum and Thelotrema subtile (see p. 

31s). 

A euoceanic moss-dominated facies of the Lobareoz in south-west Ireland 

characteristically includes Leptogium brebissonii, L. burgessii, Lobaria 

pulmonaria, Porina hibernica, Pseudocyphellaria lacerata and Sticta 

canariensis (the S. dufourii morphotype occurring in deep shade). 

In western Ireland (particularly in the Burren, Co. Clare; e.g. Poulavallan, 

Den of Clab) a facies of the Lobarion occurs on Corylus in relict 

Corylus woodlands of the limestone pavements. In this community 

Lobaria species are now lacking (currently restricted to mixed Quercus 

forest areas in Ireland) but Pannaria, Parmeliella and Sticta species are 

abundant and Leptogium burgessii, Normandina pulchella. and (Jsnea 

10. Lichen Communitt)es in the Ilritish Isles 327 

specics occur on larger stems. Thelotrema subtile is present in these communities 

in Connemara and south-west Ireland. 

Fraxinus (Jlmus forest, especially when on basic soils over limestone, 

basic volcanic rocks, or on rich alluvial soils, supports a further distinctive 

community of the Lobarion in which, in addition to the taxa marked " 

in Table II, there is a particularly rich development of species of Pannaria 

(including P. sampaiana), Parmeliella, Collema (C. fasciculare, C. furfuraceum, 

C. nigricans and C. subflaccidum) and Leptogium (L. azureum, L. 

burgessii, L. cyanescens, L. hibernicum and L. saturninum); Lithographa 

dendrographa may also belong here. This commr,rnity is now well developed 

only in a few areas of western Scotland where it occurs both in open forest 

and on isolated well lit old trees (e.g. Loch Melfort; Ellary Woods, Loch 

Caolisport; Rassal Wood, Kishorn; Mull; Sunart; Loch Arkaig); fragments 

do, however, persist in southern (e.g. New Forest, Cranborne 

Chase) and r,r,estern England, Wales, the Lake District (e.g. Gowbarrorv) 

and parts of western Ireland. Also, as members of this community thcre 

may be the very rare British species Arctomia delicatula (euoceanic), 

Collemtt occultatum and Pannaria ignohilis (a valley species of the central 

Flighlands, often found on trees which have Bryoria capil.laris on their 

twigs). 

All. 7. Parrnelion laeoigatae 

Parmelian laedgatae all, nov.; type: Parmelietum laeoigatae P, James et al. 

(monotype). 

This new alliance contains a single association: 

Parmehletum laeztigatae ass. nov. (Table III, Fig. 4) 

This is a well marked community characteristic and general on the westcrn 

side of the British Isles, including parts of south-west Ireland, and is also 

present in western Brittany. It is largely restricted to Betula ard Quercus 

(although it can be encountered on Alnus and mossy rocks) ancl confinecl to 

exposed, often upland, woodland sites q'ith high rainfall (127-229 cm 

year 1) and with at least 180 wet days year-l. The only sites for this 

community outside the 180 wet-day isoline (see Ratcliffe, 1968; Coppins, 

7976) are in north Pembrokeshire but, were more meteorological clzrta 

available, we suspect they also would be within this isoline. 'l'he Parmelietum 

laeoigatae is esscntially an association of well lit hardwoocl forests, and 

appears to be correlated with exposure to heavy rain which leaches thc 

upper horizons of the bark. The pH of bark supporting this community is

Frc. 4. Parmelietum laez;igatae on mossy boulder. predominant species : parntel.iu 

laet:igata and Sphaerophorus globosus (Argyllshire: Salen, 1967, i. W. ;urrres;. 

1. Argyllshire, Loch Sunart, Camasine (17 17 - - 6 _ _): euercus borrgh, 0.2 m 

- diam, _l_ horizontal, I x 0.2 m, cover 90fu, SeptemL.rlSZO, F.R. 

2. Gwynedd (Merioneth), Coed Ganllwyd, below Rhaedr_ddu (2317 __2__), 

_3__ldjacent Betula pubescerrr trunks in wood, c. 15 cm diam, incl. 70., aspect 

WSW, 1 x 0.4 m, cover 7|o/o, I April 1975, F.R. 

3. Gwynedd (Merioneth), coed Maen ymenyn (23/g4g355): siriceous rock 

. !oulde1, incl. 80u, aspect SE, 1 x 1 m, "o0,". 

?07o, zl tuur.i 1975, F.R. 

4. Cumbria, Borrowdale, Castle Crag Woods (3512 - -' 1 _ _): euercus prtroro, 1 ^ 

diam, incl.85', aspect SE, 1 x 0.5 m, cover 100]i, Z:Z luty iOZt, n.n.; 

tltpe record. 

5. cumbria, Eskdale, Dalegarth woods (3412 - - 9 - -) : euercus in wooded ghyll 

below Stanley Force,0.8 m diam, incl.90', aspect N, I x 7 rn, cover 90(f;,, 

25 July 1970, F.R. 

6. Cumbria, Borr - 1 _ _): eueruts petraea 

_ in woodland, 0 70,)l,,2.S yrly tUZt, f.n. 

7. Cumbria,Borr p-_1__):ettercuse) 

in woodland, 0 5 m, cover 90N,,26 July 

1971, F.R. 

8. Cumbria, Borrowdale, Seatoller, Low Stile Wood (35/2 __1__): euercus 

petraea in open ye6dland, 0.5 m diam, incl. 90., aspect SE, 0.5 x 0.5 m, 

cover n.a., 27 luly 1971, F.R. 

Species 

C etr e lia olir.t etorum s.l. 

Cladonia chloroPhaea 

C. coniocraea 

C. ochrochlora 

Cornicularia aculeata 

Eoernia prunaslri 


H. tubulosa 

Menegazzia terebrata 

Micarea sp. 

My cob I.a stus s artg uinarius 

Ocluolechia androgyna 

O. tartarea 

Parmelia crinita 

P. glabratula 

P. laeoigata 

P. saxatilis 

P. taylorensis 

Pertusaria amara 

Platismatia glauca 

Sphuerophortrs globosus 

Usnea hrflata 

U. subfloridana 

B arhi.lophozia atteil.uata 

B. floerhii 

Bazzania trilobata 

Dicranutn fuscescetts 

D. scopariunt 

Dipktphyllum albicans 

Frullania tantarisci 

Hypnum cul>ressiforme 

I s o the cium my o s ur oi d e s 

Lepidozia reptans 

Lophozia ztentricosa 

Plagiochila ?unctata 

Polytrichum fonnosum 

Rhacomitrium 

heterostichum 

Scapania gracilis 

Algal crust 

TesI-r III. 

Parmelietum laeaigatae ass. nov. 

7.2 

1.2 

7.2 

2.3 

i, 

2.2 

)') 

L.;\ 

2.2 

J.J 

L) 

_ -L) 

\.r 

)-2 

+.0 

1.2 

_L) 

+.3 

1.3 +.2 

,,n 

1.3 +.2 

L) -t ) 

I ,L t.L 

7.2 

t) 

- 2.3 

- 

- 

.t..1 

1.2 

- +.0 

_ 7.2 

- 1.2 

Stands 

45 

J.J 

2.3 

t,) 

2.2 

-F.0 

7.2 

+.+ 

+.0 

1.2 

+.2 

7.2 

t.2 

)') 

2.3 

1,.2 

3.+ 

1.3 

2.3 

L,) 

1.3 

2.2 

)1 

L) 

t,

330 P. W. James, D. L. Hawkszrorth and 1-. Rose 

in the range pH 3-75-+.60, contrasting with the Parmelion 1>erltttae antl 

Lobarion pulmonariae with bark pH valucs almost always over pH 5.0 and, 

in the case of the latter, sometines over pIJ 6'0. 

The Parmelietum laeoigatae is particularly characteristic of the following 

areas in Britain: 

1. High-level oak woods round the edges of Bodmin Moor, Cornu,all, 

at 650-750 lt (c.220-230 m), 

2. Exposed upland oak woods of Dartmoor, Devonshire (e.g. 

Tor Copse, Wistmans Wood), at 1200 1450 ft (r. 360-440 m), 

3. Upper parts of valley oak woods on Exmoor and the Quantock 

Black 

Hills, 

Somerset, 

4. Oak-birch woodland in high rainfall areas of the Lake l)istrict, 

5. Upland oak lr,'oods in r,vestern \Vales, at 600-1500 ft (c. 200-450 m), 

and 

6. Generally in more exposed oak-birch woodlands in western Scotland, 

at 150-1200 ft (c. 50-360 m), as far north as Wester Ross. 

Altitude appears to be less important than exposure to rain-bearing 

winds in determining its occurrence. Oak woods below the indicatecl 

levels, if sufficiently undisturbed, support the Lobarion pulmonariae. 

Transitions between these communities are very abrupt in southern 

Britain (e.g. on f)artmoor and Exmoor), but much more gradual in 

western Scotland. 

Fragmentary forms of this association occur in valley bottoms throughout 

u'estern Britain on the naturally more acid bark of Alnus. This association 

is primarily characterized by Mycoblastus sanguinarius, Ochrolechia 

androgyna, O. tartarea, Parmelia laeoiga.ta and P. tayl.orensis. Other 

species largely faithful to it include Bryoria smithii, Cetrelia oliz.etorunt 

s.1., Menegazzia terebrata, Parmelia endochlora and Pertusaria ophthalmiza 

(in Scotland). Sphaerophorzs species are frequently important components, 

Cladonia species are often present, and the community is rich in calcifugc 

bryophytes, particularly Dicranum scoparium, Hypnum cupressiforme var. 

fliforme, Isothecium myosuroides, Plagiochila punctata, P. spinulosa anrl 

Scapania gracilis. 

Where this association occurs on mossy rocks and boulders it is usually 

in those upland woods where it is also present on the trees. 

Al1. 8. Parrnelion perlatae 

Jtarmelion perlatae nom. nov. Trichoterion Laund., Lontl. Nat. 37, 73 (1958) 

lnom. illegit.].-Pannelion caperatae Barkm., Phytos. Ecol. Crypt.,l,/r., 450 (19-59) 

fas "suballiance"] ; type: Parmelielum reztolutae KIem. l\on Parmelion caperoto? 

Felf., Acta geobot. Htntg.4,55 (1941); type: Parmelietu'm ca1>erutae lelf. 

10. Lichen Comm.unitie.r in the Britislt Isles 331 

?Nonl)arnrelionperlatae Iiollm., Ber.dtsch.bot.Ges.80,201 (1967)lnom.nud.]; 

type not stated. 

This alliance, in its various facies, is the characteristic community of 

well lit maturc dcciduous trees in areas of little or no air pollution in 

lor.r'land Britain. In north-eastern England, central Wales and central and 

eastcrn Scotland the alliance is replaced by the Pseudexernion.furfuraceae 

as thc dominant epiphytic community of well lit trees" 

The I'armelion perlatae is characterizedby the abundance of Parmelia 

caperata and P. perlata. A single very variable association within it is 

recognized here as present in the British Isles. 

Parmelietum revolutae Klem. (Table IV) 

Beih. Feddes llepert. 135, 163 (1955) [as "Almborn 1948"1.-Parm.elietum 

rexoluta.e var. parm.eliosum, laeteoirezfri' Barkm., Phytos. Ecol. Crypt. Ep., 452 

(1958) lnom. .utperfl.].-Parmelietum rez;olutae var. caperatosum Barkm., Phytos. 

Ecol. Crypt. Ep., 454 (195U). Parmelietum cerxicornis Duvign., Bull. Soc. r. bot. 

8e1g.74,.47 (1942)lnom.illegit.].-Parmelietumsubauriferae Duvign., Bull. Soc.r. 

bot. Ilelg. 74, +7 (1942).--Parmelietum trichotero-scortea Barkm., Phytos. Ecol. 

Crypt. l|p.,450 (195S).-Non Parmelietum caperataeFelf ., Acta geobot. Llung.4, 

ss (1e41). 

This association is best developed on the trunks and ascending boughs of 

Fraxinus, Quercus, Larix (in Ireland) and other rough-barked trees of 

0'3-1'0 m diam in parklands, by minor roads, in pastures and more open 

woodlands; it is restrictcd to upper u.ell lit parts of trees in dense woodlands 

wlrerc it may occur above a zone of either Lobarion or Graphidion. 

Thc association has a very wide phorophyte range, however, and will also 

occur on the smooth bark of Fagus, Acer and (.tlmus species where the bark 

has not been unduly enriched by dust or animal matter. Sulphur dioxide 

pollution and agricultural chemicals impoverish it to varying degrees. 

With increasing bark acidity it tends to grade into the species-poor facies 

of thc Pseudevernietum furfuraceae (see p. 335), whilst r.vith decreasing 

bark acidity the Buellietum punctiformes or algal-dominated communities 

mav be produced. Although not usually encountered on coniferous trees, 

in the most unpolluted parts of southern and western Britain (particularly 

near thc sea), it is occasionally found on mature u'ell lit trunks of Picea abies, 

Pinus sylxestris and Larix. Most pII values from bark beneath this association 

fall within the range pH 5'0-5'5. 

'l'he Parrnelietum reztolutae is best developed in southern and western 

lorvland areas, occurring today in the eastern and northern parts of East 

Anglia, throughout the counties south of the Thames, west lVlidlands, 

Welsh lowlanc{s (especially near the coast), Lake District, lowland coastal

334 P. W. Jam.es, D. L. Hawhsusorth and F. Rctse 

encounte re cl being Dicra.noweissia ciwata, Flypnum. cupressiforme and 

C)r thotric hum ly ellii.. 

'lh.e Parmelietum rexolutae is particularly rich in species and many 

others, in addition to those mentioned above, occur from time to time in 

varying amounts. Nevertheless, only two species approach bcing strictly 

faithful to it in Britain: Parmelia soredians (which also rarely occurs on 

dccorticate wood and stonework) and P. reticulata (most frequent in the 

cast and south-east). It is perhaps unfortunate that the name of this 

association is based on that of P.reaoluta as that species is not particularly 

common in it, tending to be most frequent in either slightly shadecl sites 

or on the smoother and less water-retentive bark of Alnus and Fagus in 

southern woodlands. ln Kent and East Anglia P. acetabulum, tt:'ore 

characteristically a species of the Xanthorion, also occurs in the Parmelietum 

rexolutae as it does in parts of Belgium and France; this phenomenon may 

be correlated with climatic factors approaching those optimal for this 

particular species (i.e. generally drier and warmer summers). 

The original record of the Parmelietum caperatae Felf., described from 

Hungary, is even more transitional between the P. reoolutae and the 

Xanthorion as it included not only Parmelia acetabulum but also Anaptychia 

ciliaris, Physconia pulaerulenta and Xanthoria parietina. Felfoldy's name is 

thus not taken up for the Parmelietum reoolutae here; his community may 

be referred to the Parmelietum acetabulae var. parmeliosum caperatae 

Ochsn. (Ochsner, 1928: 62)" 

All. 9. Pseudeoernion furfuraceae 

Pseudezternion furfuraceae (Barkm.) conrb. nov. Parmelion furfuraceae Barkm., 

Phytos. Ecol" Crypt. Ep.,456 (1958) [as "suballiance"], basionym; type: Parnt.elieluru 

furluraceae Hrl.-Parmelion saxatilis Barkm., Phytos. Dcol. Crypt. Ep., 

450 (195ti) ; type: Parmelietum.furJuraceae Hrl.; nom. illegit. lnon Parmelion 

saxatilis Klem., Ber. bayer. bot. Ges.28,257 (1950); type: Parmelietum conspersae 

Klem.]. Physodion Waldh., K. soensha VetenskAhad. Aoh. natur. 4,90 (1944); 

type: "Parmelia physodis-fdrbundet DR. 1942".-Parmeliop.ridion ambigtae 

Barknr-, Phytos. Ilcol. Crypt. E1>.,466 (1958) fas "suballiance"];type: Parmeliopsidetum 

ambiguae "Hil."-See a/so Follmann (1974). 

This alliance, rrrost frequently termed the "Physodioa" by British authors 

since Laundon (19-56), is essentially a northern, more acidic substratercquiring 

counterpart of the Parmelion perlatae in thc British Isles. It is 

characteristic of trecs with modcrately acidic barks in wcll lit situations 

and is widespread throughout large areas of northern England, central 

Wales and central and eastern Scotland. Under pollution stress, where 

bark tends to becorne somewhat acidified, it occurs further south as 

10. Lichen Cctmmunities in the British Isles 335 

species-poor communities. While in Scotland it is widespread on conrferous 

and deciduous trees, in areas not subject to pollution stress in 

southern England it is mainly restricted to coniferous trees, birch and 

fence-posts. These factors suggest it tends to prefer more acidic substrates 

than the Parmelion perlatae. It largely replaces the Parmelion l>erlatae it 

lowland Scandinavia east of western Norway. 

T'he Pseudexernion furftraceae rs not exclusively corticolous, holever, 

and has similar associations and compositions when growing on siliceous 

rocks. It is found throughout the British Isles on acidic rocks whcrever 

these occur. The characteristic species of the alliance are Bryoriafuscescens, 

Cetraria chlorophylla, Ilypogymnia physodes, H. tubulosa, Ochrolechia 

androgyna, Pa.rmelia saxatilis, P. sulcata, Parmeliopsis ambigua, Platismatia 

glauca and Pseudexernia furfuracea. Two associations in this alliance may 

be recognized in the British Isles at the present time. 

Pseudeaernietum furfuraceae (Lhl.) Kalb (Table V) 

Diss. Bot., Lehre 9, 59 (1970). Parmelietum fttrfuraceae Hil., Spisy Pilrod" 

Fac. Karl. Uniz:. 41, 122 (1925) fas "Association i. Parmelia furfurncea"l.- 

Parm.elietnm fur;t'uraceae-physodes Frey & Ochsn., Arvernia 2, 78 (1926). Pttrmelietum 

saxatilis Hil., op. cit. 41, 143 (1925) [as "Associationb. Parmelia sa.uatilis"f.-Parmel.ietum 

sulcatae lIil., op. cit" 41, 151 (1925) [as "Association i 

Parmelia sulcata"l.-Hypogymnio physodis-Partneliehtm saxatilis Wirth, "/)zis. 

Bot., Lehre 17, 211, (1972) las "(Hil. 1927) nom. nov."]. Physodeto-sulcatetum 

DR., SzezsA bot. Tidshr. 39, 14U (1945)"-Physodetum Almb., K. sxenska 

VetenskAkad. Aoh. natur" 11, 39 (1955).-Parmeliopsidetum ambiguae subass. 

platismatietosum glaucae Kalb, Hoppea lDenkschr" Regensb. bot" Ges.] 30, 84 

(1972). -See also Follmann (197+)" 

This association is very variable and some authors have recognized 

numerous subassociations and variants within it (e.g. Barkman, 1958; 

Fabizewski, 1968; Kalb, 1970); Hawksu,orth (1969) noted the presence of 

several of these in Derbyshire. Essentially it has a composition as for the 

alliance but can be simplified under air pollution stress to Hypogymnia 

physodes-Parmelia saxatilis Platismatia glauca communities (sometimes 

with Pseudeaernia furfuracea) such as are particularly widespread and 

luxuriant on trees and siliceous rocks over large areas of central and 

northern England. Bryoria fuscescens is particularly common in the north 

and in upland areas of the south-west (e.g. Dartmoor). Facies rich in 

Parmeliopsis ambigua are also not uncommon under moderate pollution 

stress. A valuable rdsumd of the syntaxonomy of this association and its 

composition is provided by Follmann (1974). 

In the south, Exernr.a prunastri, Lecanora pallida, Pertusaria amara arrd

Species 

Bryoria fuscescens 

Calicium airide 

Cetraria chlorophylla 

Eaernia prunastri 

Huilia macrocarpa 

Hypogynmia physodes 

H. tububsa 

Lecanora conizaeoides 

L. ex1>al.lens 

L. intricttta vzr, 

sorali.fera 

L. scalaris 

Lepraria incana 

M y c ob I a s tus s anguinarius 

Ochrolechia androglna 

O. tunrcri 

Parmelia glabratula 

P. saxa.tilis 

P. sulca.ta 

Parmeliopsis hyperopta 

P. ambigucr 


Platisnntia glauca 

Ps eudeoer nia furfur ac ea 

(Jsnea hirta 

LI. subfloridana 

Tenln V. 

P seudea ernietum furfur ac eae (Hil.) Kalb. 

466 

+ 

+ 

+66 

+ 

+ 

Stand 

56 910 

+7 

-+ 

-i 

3+ 

+ 

1_ 

52 

1. E. Inverness, Rothiemurchus Forest, Loch an Eilein (27 1895027): Larix 

europaea,rncl.79", aspect 130', pH 4.02, 10 x 10 cm, cover 58%,, 3 August 

1968, D.L.H. 

2. E. Inverness, N. of Croftmore, near Boat of Garten (281945175): palings by 

roadside, incl. 0', aspect horizontal, pH 4.38, 10 X 10 cm, cover 807., 4 

August 1968, D.L.H. 

3. E. Inverness, Glen More Forest (28/985078): Pinus syloestris ssp. scotrca, 

incl. 73', aspect 270", pH 4-02,10 x 10 cm, cover 81o/o,4 August 1968, D.L.H. 

4. E. Inverness, near Croftmore, near Boat of Garten (281934154): Betttla sp., 

incl. 71 ", aspect 225", pH 4.67, 1 0 r 10 cm, cover 7 2o/n, 4 August 1 968, D.L.H. 

7- 

,) 

57 

-6 

87 


preference see under the alliance above' 

P armeliopsidetum ambiguae F tey 

Ver. naturf. Ges. Basel 35, 319 (1923).-Parmeliopsidetum DR., Svensh bot- 

Tidshr.39, 148 (1945). 

This community is rather poorly represented in the British Isles where it 

is found mainly on decorticate coniferous wood in central and eastern 

Scotland. It is also sometimes encountered on conifers and birch trees 

themselves, however, and is clearly closely allied to the Pseudeoernietum 

furfuraceae from which it differs in the abundance of Parmeliopsis aleurites, 

P. ambigua and P. hyperopta. It should be noted that this community is 

quite distinct from the Parmeliopsis ambigua-rich facies of the Pseudeoernietum 

furfuraceae sometirnes developed under pollution stress (p. 335). 

At first we were inclined not to recognize this syntaxon as distinct in 

Britain but an examination of the data of Frey (1923) and Barkman's 

observations (1953) shows that the Parmeliopsis-rich communities of the 

Scottish Highlands are most probably species-poor variants of this association. 

Additional characteristic species of this essentially subboreal association 

now rarely found in Britain include Cetraria juniperina, C. pinastri 

and C. sepincola. In northern Europe this association appears to be 

5. Lanarkshire, between Coulter and Biggar (3610 - - 3 - -) : Fraxinus excelsior, 

incl. 90", aspect 205', pH 4'77,10 x 10 cm, cover 90o/o,29 July 1968' D'L'H' 

6. Peeblesshire, NE of Dolphinton (3611 --+--): Fagus sylz;atica, incl. 82", 

aspect 180", pH 5'25,10 x 10 cm, cover 600/0,29 July 1968, D.L.H. 

7. Derbyshire, Birchover, Rowtor Rocks (43/235622): millstone grit rocks, 

incl.60", aspect225",10 x 10 cm, cover 70(%,28 August 7967'D.L.H. 

8. Sutherland, Halladale, near Achiemore (2918 -- 5 --): Old Red sandstone 

outcrop, incl. 82", aspect 270', 10 x 10 cm, cover 80o/o'12 August 1968, D.L'H' 

9. Derbyshire, Chatsworth, near Beeley Lodge (431265684): millstone grit wall, 

incl. 0', aspe ct horizontal, 10 x 10 cm, cover 80f,1, 4 April 1967, D.L.H. 

10. Derbyshi.", Hollo*uy, Dethick Lea Hall Farm (43/335575): millstone grit 

wall, incl.0', aspect horizontal, 10 x 10 cm' cover 1007;, 15 March 1967, 

D.L.H.

338 P. II/. James, D. L. Llawhsuortlt and F. Rose 

particularly frequcnt on birch trvigs, and commtrnities with Cetraria 

chlorophylla, C. sepincola and Parmelia septentrionalis on birch tu'igs in 

the Scottish Highlands are thus placed here. 

The synsystematics of the Parmeliopsidetum ambiguae, discussed in 

some detail by Barkman (1954), remain poorly understood. A considerable 

number of taxa at subassociation and variant ranks have been described 

in it which requirc re-evaluation on a European scale. 

All. 10. Usneion barbatae 

Usneion barbatae Ochsn., Jahrb. St. Gall. naturw. Ges. 63,68 (1928) ; type: 

Usneetum barbatae Ochsn.-Uszeion dasypogae Barkm., Phytos. Iicol. Crypt. Ep.. 

475 (1958); type: Usneetum dasypogae Frey [: Letharietum diaaricatae Freyl. 

Usneion florido-ceratinae Barkm., Phytos. Ecol. Crypt. Ep.,+70 (1958); type not 

designated. 

Communities dominated by species of (lsnea, characteristic of acidic 

barks and usually in very well lit situations are placed in this alliance. The 

synsystematics of this alliance in Europe are, however, in a confused state 

mainly as a result of the currently unsatisfactory species concepts in many 

groups of Llsnea species. Five associations can be distinguished in the 

British Isles, but the names of four may require some revision when the 

identity of some (Jsnea spccies used to characterize alliances in continental 

Europe becomes firmly established. 

All associations of this alliance are very sensitive to air pollution and so 

have more restricted distributions in the British Isles than they did in the 

early parts of last century. 

C ladoni e t o - LI sne et um tulter c ul at ae Barkm. 

Phytos. Ecol. Crypt. l:p., +77 (1958). 

'fhis association is treated here in the sense of Hawksworth (1972a) to 

include communities allied to the flsneetum subforidanae in more shaded 

habitats where Cladonza species (".g. C. coccifera, C. pyxidata, C. squamosa) 

and bryophytes form major parts of the stands. Also sometimes encountered 

on acid mossy rocks, this association may perhaps be viewed as an intermediate 

betu'een the L/. subforidanae and the Cladonietum coniocraeae. 

Llsnea fammea, II. .fragilescens and (J. inltata (syn. U. intexta) are to be 

found in this association in more upland areas in addition to U. sub- 

Jloridana. 


Rantalinetum f astigi at ae Duvign' 

Bull. soc. r. bot. Bel.g. 74, +2 (1942).- See Barkman (195t3) for lists of probable 

synonyms. 

all of which occur in the British Isles, but they do not appear to merrt 

separation as transitions are commonly encountered' 

t'" 

*'-L' 

{J r-' 

j 

Predominant species: 

fastigi.a t.a, R. Frc. 5. Ramalinetum fastigiatae on nutrient-rich bark' 

Eaernia prunastri, Physcia tertella, Rannlina farinacea, 1l' 

-frutittea 

and Xaitlrcria parietina (W. Inverness: Invergordon, \976, 

R. O. Nlillar). 

339

340 P. W. James, D. L. Hawhsworth and F. Rose 

Although this association has generally been placed in the Xattthorion 

we suspect that it may be more closely allied to the (Jsneion as it parallels 

the (Jsneetum articulato-foridae b:ut is found in somewhat more nutrientrich 

sites. Some tendency to intergrade with the Llsneetum sultfloridanae 

also supports its positioning here. 

U sne etum artic ulato-floridae v ar. c er atinae D. Hawksr.r'. 

Fld stud.3,5+3 (1972). 

This often spectacular community (Fig. 6), which characteristically occurs 

in very well lit situations and is optimally developed on the uppermost 

sloping or horizontal boughs of trees, has a markedly southern and southwestern 

distribution in the British Isles. The most important species of 

the variant are Usnea articulata, U. ceratina, U. florida and U. rubiginea, 

although U. inflata (syn. U. intexta) and U. subfloridana are often also 

present. 

In the southern counties of England a facies dominated by U. cet,atinu 

and U. inflata occurs not uncommonly on almost vertical lvell lit trunks of 

Fagus and Quercus in glades; U. articulata is generally absent in this 

facies although U. rubiginea is often present. This nodum may in future 

merit separation as a distinct association. 

The "typical" variant of this association, as interpreted by Barkman 

(1958), is still present in Brittany and includes Heterodermia leucomelos, 

Pseudocyphellaria aurata and Teloschistes flaaicans. These species are now 

very rare in Britain, perhaps prefer more nutrient-rich barks, and seem 

better placed in a separate association, the Teloschistetum flavicantis (p. 

348), which is always poor in (Jsnea species. The relationships between 

this community and both the Usneetum forido-neglectae Bibinger and the 

Llsneetum rubicundae Barkm., both unrecognized in Britain, merit further 

study. 

Usneetum filipendulae ass. nov. prov. 

This poorly understood association, which is not validated here in the 

absence of detailed records, is characteristic of ancient coniferous forests 

in Scotland and dominated by Usnea filipendula and U. fbrillosa. Alectoria. 

sarmentosa, Bryoria capillaris, and sometimes (J. hirta, may be further 

important components of this association. It should be noted that this 

commr,rnity may perhaps be in reality a species-poor variant of the central 

and northern European montane (Jsneetum barbatae Ochsn. (for which the 

later name Letharietum dioaricatae Frey was employed, perhaps unnecessarily, 

by Barkman, 1958), 

Frc. 6. (Jsneetum articulato-floridae var. ceyatinae on salix in marsh' species 

present include Eaernia prunastri, Hypogymnia pl'4tsodes, Parmelia perlata, P. 

sulcata afld (Jsnea ceratina (s. Devon: slapton, Duck Marsh, 1975, F. S. Dobson).

3+2 P. W. James, D. L. Hazahszoorth and F. Rose 

(Jsneetum subforidanae D. Hawksw. 

Ftd stud. 3, 5+3 (1972). 

All. 11. Xanthorion parietinae 

10. Liclten Communities in the British Isles 3+3 

'lhe lfamalinetum .fastigiatae, placed in this alliance by rnost previous 

authors (e.g. Barkman, 19-58), is referred to the {tsneion barbatae hcre (see 

p. 339) and is thus not trcated belolv. 

Buellietum punctiformis Barkm. 

Phytos. Ecol. Crypt. Dp.,405 (1958). 

A frequcntly specics-poor association comprising mosaics of Buellia 

punctata, B. canescens (somctimes dominant), Candelariella reJlexa, C. 

ztitellina, Lecania cyrtella, Lecanora chlarotera, L. sambuci, Lecidella 

elaeocfuoma, Lecr)dea quernea and often also with Xanthoria species. This 

community is characteristic of nutrient-enriched or hypertrophicated 

barks and particularly common in areas of moderate sulphur dioxide and 

inorganic iertilizer pollution where other associations are not able to 

develop. It becomes rarer in the cxtreme north of England and Scotland. 

Gyalectinetum carneoluteae D. Hawksw. 

Fld stud.3,5+5 (1972). 

A shade-loving community of nutrient-rich barked trees of the extreme 

south and south-west Englancl characterized by an abundance of Gyalectina 

carneolutea. Other important components of this community are Bacidia 

phacod.es, B. rubella, Lithographa dendrographa and, sometimes, O1>egrapha 

prosodea. Better lit facies shou' some intergradation with thc Buellietum 

punctiformis, whilst more shaded ones include elements of the Pyrenuletum 

nitidae. Thc presence of Lithographa dendrographa nay indicate that this 

association has some affinity to the Lobarion pulmonariae (see p. 327). 

P a,rme lietum. c ar porr hi z anlr Crespo 

An. Inst. bot. A. .1. Caaanillo 32, l9l (1975). 

Parmelia. quercina (syn. P. carporrhizans)-dominated communities occur 

in Britain on very rvell lit and slightly nutrient-enriched parts of trees, 

most frequently the upper branches. This is largely a southern Europcan 

association, however, ancl is only found in the British Isles with any 

frequency in the low-rainfall and high-sunshine coastal parts of south 

Dcvonshire and Dorset where P. borreri and P. pastillifera are also characteristic 

of it. Crespo (197-5) recognized tu'o variants and one subassociation 

(the parmelietosum endochlorae). IIis first variant, with the diffcrential

34+ P. I1r. James, D. 1,. I-Iazpksutorth and F. Rose 

species P. caperata and P. soredia.ns, is thc type representecl in the tsritish 

I sles. 

carporrhizanrls has many features in common with the 

but as it prefers more nutrient-rich sites, it is referred 

arietinae- 

P ar me lietum e leg ant ulae Klem. 

Beih. Feddes Repert. 135, 154 (1955) [as "Armborn 1g4g,,1.-parnulietwtt 

lacinintulae Barkm., Phytos. Ecol. crypt. 8p.,446 (195g) fas ,,(Almborn) Klement 

1ess"l. 

This association, distinguished by the frcquency of parmelia eleganttila, 

P. laciniatula and often ochrolechia yasudie, shorus strong affinities u,ith 

both the P. acetabulum facies of the physcietum ascendenis and. the parmelietum 

rexolutae- The Parmelietum elegantulae is particularly u,ell 

developed in sites alTected by man and appears to require a somcwhat 

lower bark pH than the Physcietum ascendentis.It is because of this difierence 

in requirements that it is not subsumed under the physcietum ascentlentis 

here..Physcia, Physco'nia and xanthoria are of relatively minor importance 

in this association as compared to the physcietnm asceidentis. 

Physcietum ascendentis Frey & Ochsn. (Table VI) 

Araernia 2, 82 (1926).-Parmelieturn acetabulae ochsn., Jahrb. st. Gall. naturu. 

9rt.,!31.60 (1928).-Teloschistetum chrysophtharmre oc{s.r., Reztue bryor. ricrtin" 

7' 85 (1934) .-Xanthorietum candelarite Frey, Irrgebn. uiss. Llnteri. schueiz. 

NatnParhs, n..f .3, 476 atue Barkm., phyros. Dcol. 

9:o^p}.Ê-p,,400 (1958). ., phytos. Ecol. Crypt. Dp., 

369 (1958).-See Bark synonyms of these names. 

The Physcietum ascendentis is treated in a rather broad sensc here to 

include the majority of Physcia, physconia and, Xanthoria d,omrnated 

communities of nutrient-rich bark in the British Isles. The nurrerous 

associations and subassociations recognized for these by continental 

authors appear to be of limited syntaxonomic importance here. The 

association is primarily distinguished by high frequencies of physcia 

(particularly P. adscend.ens, P. aipolia, p. or-bicularir, i'. tenella and sometfmes_ 

P. tribacia), Physconia (P. enteroxantha, p. farrea, p. grisea and 

P_. pulaerulenta) and Xanthoria (X. canclelaria, X. filtax, x. paiietina ancl 

x. polycarpa). The association is often very rich in-species *itti:o or more 

not infreque'tly present on single, mature, wel rit, nutrient-enriched 

trees in areas of little air pollution. The preclominant species may vary 

from tree to tree .rr"., *,h"n these are in close pro*imity and so this 

10. [,ichen Com.mtni.ties in the Rritr)sh Isle.t 34-5 

appears to be of rather limited syntaxonomic value. Communitics falling 

within the concept of thc Parmelietum acetabul.ae (including Anaptychia 

ciliaris, Parmelia acetabulum, P. exasperatula or P. tiliacea) represent an 

eastern facies (Table VI) of the association in Britain and are particularly 

well developed on u'ell lit mature tree trunks in open parkland sitcs;this 

might be intcrpreted as a distinct variant or subassociation but, as it could 

also bc viewed as the species-rich or optimal facies of a single association 

which becomes simpli{ied both northwards and westu'ards in response to 

climatic stresses progressively climinating specics, it is not trcated separately 

here. The abundance of Rarnalina species in thc association appears 

to be related to the degree of exposure, these bccoming most frequent in 

well ventilatcd sites. 

Some communities of this association in central and eastern Europe 

may have some affinities vvith the Parmelietum retol.utae (see p. 331). 

Although primarily corticolous, species-poor communities referable to 

this association are occasior.rally cncountered on nutricnt-cnrichcd calcareous 

rocks where they can, whcn optimally clevelopcd, incluclc evcn 

Anaptychia ciliaris. 

A community of nutrient-rich (llmus woocl tracks dominatcd by Baciditt 

incompta but including Caloplaca luteoalba is lentativcly mcntionccl here 

but may mcrit association rank. 

Physcietum clesiae Mot. 

See p. 360 for details of nomenclature and composition. 

Although primarily saxicolous, this association is sometimes v'cll developcc{ 

on trees or timber heavily imprcgnated with alkaline dust, for example 

near limestone-crushing plants and ccment works (sec Gilbcrt, 1976). In 

such situations the corticolous community includcs species normally 

found in it when it occurs on calcareous substrates (e.g. Lecanoramut'alis, 

Phltscia caesia). 

Physciopsidetum elaeinae (Barkm.) comb. nov. 

Physcieturu elaeinae Barkm., Phytos. Iicol. Crypt. Dp., 414 (1958). 

This association, closely allied to the Buellietum punctiformrs, is encountered 

on highly hypertrophicated bark, particularly of Sambucus. The variant 

buelliosum canescentis Barkm. is the facies represented in the British lslcs 

and is distinguished by high cover values of Physciopsis adghiinata (and 

sometimes Physciaorbicularis and P. tribacia).'I'he Physciopsi.detum elaeintte 

tends to prefer slightly more shaded habitats and smoother bark than the 

Physcietum ascendentis. Barkman (1958) considered this to be orirnarily a

Species 

Tasrn VI. Tesrn Yl-continued 

Physcietum ascendentis Frey & Ochsn. (,,eastern facies,,). 

Acrocordia gemmata 

Anaptychia ciliaris 

Arthonia impolita 

Buellia canescens 

B. puttctata 

Calicium oiride 

C an delar iella oitellina 

Catillaria grffithii 

Eternia prunastri 

Gyalecta flotowii 

H aematomma o c hr oleu c um 

var. porphyrium 

Lecanora chlarotera 

L. conizaeoides 

L. clispersa 

L. expallens 

Lecidea quernea 

Lecidella elaeochroma 


L.'incana 

Ochrolechia turneri 

O. yasudae 

Opegrapha ,uaria s.l. 

Parmelia acetabulum 

P, caperata 

P. elegantula 

P. glabratula 

P. laciniatula 

P. perlata 

P. saxatilis 

P. subaurifera 

P, sttbrudecta 

P, sulcata 

P. tiliacea s.l. 

Pertusaria al,bescens 

var. corallina 

P. amara 

P. coccodes 

P. hymenea 

P. pertusa 

Stands 

45 

t) 

- 3.+ 2.3 1.2 _ 3.3 2.2 2.3 

r.0 

+.2 +.2 +.0 7.2 +.2 +.2 t.2 7.2 

+.0 1.3 +.0 

2.3 

+.0 1.3 - +.0 

8 

Species 

Physcia adscendens 

P. aiPolia 

P. leptalea 

P. orbicularis 

P. tenella 

1.2 +.1 +.0 +.1 +.2 +.0 +.0 +.0 Physciopsis adglutinata +.0 

- +.0 

2.2 2.5 

+.0 

_ 1C 

\.L 

P. grisea 

P. puloerulenta 

Rarnalina baltica 

R. farinacea 

R. fastigiata 

Rinodina roboris 

Leucodon sciuroides 

Orthotrichum 

diaphanum 

Porella platyphylla 

Tortula laeoipila 

Zygodon oiridissimus 

+.0 

- 

Stands 

+5 

Physconia enteroxantha - +.0 

Schismatomma decolorans +.0 +.0 

Xanthoria parietina - 2.3 1.3 1.2 +.0 -I-.2 - 1.3 

Camptothecium sericeum - 1.+ +.2 1.3 2.+ 

Hypnum cupressiforme - 2.3 1.2 +.2 

1.3 

_ -L1 _L) 12 

I !r | .2 

- 7.2 

_ t ? _ 

1. Hertfordshire, North M)'rnms Park (5212--0--): Ulmus procera in open 

park, 1'5 m diam, incl. 85", aspect W, 1'0 x 0'5 m, cover 30yo,26 October 

1968, F.R. 

2. E. Kent, Bourne Park(6711--5--): Ulmus Procera,0'8 m diam, incl. 90', 

aspect SW, 0'3 x 0'3 m, cover 70o/o, 16 March 1967, F.R. 

3. E. Kent, Denton Court Park (6112--4--): Fraxinus,0'8 m diam, incl. 

90', aspect S, 1'0 X 0'3 m, cover not indicated, 8 June 1968, F.R. 

4. E. Kent, NE of "Tudor House" roadhouse E of Bearsted (51/8--5 --): 

Fraxinus in parkland, 1'5 m diam, incl. 90', aspect S, 2'0 x 1'0 m, cover 75o/n, 

4 September 1968, F.R. 

5. E. Kent, Maidstone, Mote Park (5117 - - 5 - -) : Acer campestre, 0'6 m diam, 

incl. 90", aspect SW, 1'0 x 0'5 m, cover not indicated, 10 September 1968, F.R. 

6. W. Norfolk, Hilborough Park (53/8--0--): Fraxinus in parkland, 0'7 m 

diam, incl. 90", aspect SW, 0'5 x 0'5 m, cover 80o/o, 5 June 1970, F.R. 

7. W. Suffolk, Ickworth Park (52/8 --6--): 

Acer campestre in open parkland, 

0'6 m diam, incl. 90", aspect N, 1'0 x 0'5 m, cover 60yo, 28 September 1968, 

F.R. 

8. E. Sussex, IJdimore (51/8--1--): Acer campestre,0'6 m diam, incl. 90", 

aspect S, 1'0 X 0'5 m, cover not indicated, 15 April 1968, F.R,

348 P. W. James, f). L. Jlawkszoorth and F. Rose 

Mediterranean association anc{ thus it is not surprising 

British 

to note 

Isles, it 

that, 

appears in 

to 

thc 

be most fr.q,,.rrt i., ,o.rtt 

Barkman 

n.gf^"a.^,Cf 

regarded physcia though 

clementei;; ;; ".rl 

association, ".o--'niii.. i".r"ai.f il' .il:i"'J"il .,"#r,;ffil^"t 

seem sufficiently distinctive to 'r,arrint treatment as a distinct association, 

the T elo s c his t etum fl aztic antrc. 

Teloschistetum flavicantis ass. nov. (Table VII) 

This previously unrecognized association recalrs, 

prove 

and 

to 

may 

be 

e'entually 

identical to, , 

Barkman's (1958) unnamed southern 

and montane-Mediterranean Atlantic 

variant oi the physcietunt 

ascendezlzs 

physciosum subass. 

leptaleae Klem. which h. .on.iJ"r.i to o..,r, 

Fontainebleau, provencc i., n.ir,urry, ,.,.r. 

and the centrar Atlas Mountains. 

is 

The 

closely 

association 

allied to the physuetu* nrrurdrn* o,r, is differentli.il.i*u.ity 

by the abundance of reLschist r .p..i.. 

in 1i. ;;,:r:;";;;;;;;;;;::i'. zsiilosu.r 

France; usually only ?. yor.irars iri-nr;t^1,-r;. physcia clementei, p. 

Species 

Anaptychia ciliaris 

A. fusca 

Eoernia l>runastri 

Ochrolechia parella 

O. yasudae 


P. perlata 

Tesrn VII. 

T elo s c hrLs t e tum fl.aoic antis ass. nov. 

Stands 

72 

Additional species present in this community in 

areas of the quadrats were : Bucllia , ,rrr",rr."'L 

Leridea '": 

eucrn(:n. Lphvnvin .n-)-t.,,.:- ,^ ,' 

t l;"i,);::?" 

.I 

2 

+ + 

J 

J 

l 

2 

;-t 

4 

Species Stands 

Parmelia subaurifera 

P. subrudecta 

P. sulcata 

Ramalina farinacea 

R. fastigiata 

Teloschistes flaaicans 

Bryophyta 

t2 

2a 

-t 

3+ 

-f 

33 

.'t - 

+5 

icombe.House (201811417): mature Acer pseutto- 

87o/o, 11 A .diam' r'ncl' B5', aspect 2g0", 20 x 20-.-, "or,., 

2. S. Devon, s,_Widd.icombe House (201g11417): mature Ace.r pseudoplat.nus 

in pasture, 40 cm diam, i".1. gt-,;rp; ct265.,,20 x 20cm, cover 90(1,,, 

I I August 1973, D.L.H. ; typc rtrord." 

-L 

lij: 

10. Lichen Communities in the British Isles 3+9 

leptalea and P. tribacioides, which can form extensive stands in the sunniest 

and driest parts of southern England, are very closely associated with it. 

This community appears to have been formerly widespread in southcrn 

England but is nor'v largely restricted to thc south-west (where it is now 

much rarer than it u'as last century) from Dorset to Cornwall and is more 

rarely found in Pembrokeshire (S. Wales). The twig facies (with ?. 

chrysophthalmas) is still common in the Mediterranean area and in southwest 

France (frorn southern Brittany southwards), where it is largely 

found on twigs in very well lit situations. In south-west England today it 

occurs both on twigs and on u-ell lit, well ventilated nutrient-enriched 

tree trunks, but ?. chrysophthalmus seems now to be extinct in Britain 

outside the Channel Islands (Hawksworth et al., 1974). 

This community is not identical to the Teloschistetum chrysophthalmae 

Ochsn. (see p. 344), the type record of which lacked any Teloschistes 

species and is referable to the Physcietum ascendentis. 

IV. Limestone Cornmunities 

Hard limestones (e.g. Carboniferous and Devonian) support several 

distinct lichen communities in the British Islcs. Most of these are able to 

spread on to softer calcareous rocks ancl a wide range of basic man-made 

substrates (e.g. asbestos-cement, concrete, basic brickwork and mortar), 

but then occur esscntially as species-poor variants. 

The communities developed on coastal limestones are essentially 

species-poor facies of associations of inland limestone rocks and so are not 

recognized separately here. Some elements of the Caloplacetum marinae 

and Verrucarietum maurae, normally well developcd on siliceous rocks, 

may be encountered on hard coastal limestones, e.g. marine Caloplaca, 

Verrucaria and rarely Lichina species (see Fletcher, 197-5b). Arthol>yrenia 

halodytes can also occur on softer limestones and chalk as well as its more 

usual habitat of barnaclcs and other intertidal mollusc shells. 

Species on soil and humus in crevices, soil and turf around limestone, 

chalk, pebbles etc., are treated separately on pp. 393 +07, while intermediate 

communities on other basic rocks are discussed on pp. 361-36+. 

All. 12. Aspicilion calcareae 

Aspicilion calcareae (Alberts.) comb. nov.-l,ecanoriort calcareae Alberts., Acta 

phytogeogr. suec. 20, 3+ (1946), trasionym.-Caloplacion decipientis Klem., Ber. 

bayer. bot. Ges. 28, 263 (1950).-Gyalection cupularis Matt., Bol. |b. 75, +20


Tesrn VIII. 

Lichens characteristic o.f rimestone in the British Isres and the associations 

in which they usually occar. 

A c ar o s por a g I auc o c ar p a" 

A. heppii" 

A. macrospora" 

Acrocordia conoideab" 

A. salweyi" 

Ar thopyr enia s axicol a" 

Aspicilia calcareaoe 

A, contorta@ 

A. preoostii" 

Bacidia cupreab 

B. sabuletorum" 

Buellia canescensl 

R. epipolea" 

Caloplaca aurantia" 

C. chalybaea" 

C. cirrochroab 

C, citrina"e I 

C. decipiens" 

C. heppiana" 

C. holocarpa"l 

C. lacteao 

C. ruderurp 

C. saxicola" 

C. teicholyta" 

C. tetrasticha"c" 

C. oariabilis"" 

C. aelana" 

Candelariella aurella" 

C. medians"r 

C atill ar i a I entic ul ari s" " 

C I athr oporina c alc ay e ab 

Collema auriculqrume 

C. crispume 

C. cristatum"" 

* Apart from the Physcietum caesiae djscussed on p. 360. 

C. multiPartitum"" 

C. polyc&rPon"e 

C, tenax"" 

C. tuniformeo" 

C. undulatum" 

D u mato c ar Pon mini atumb " 

Diploschistes gyPsaceusb 

Dirina rePanda" 

D. stenhammari 

Enc eph alogr apha c er ebr in a? " 

Gyalecta jenensisb 

Ionaspis epuloticab 

Lecania erysibe"" 

Lecanora crenulata" 

L. dispersa" 

L. muralist 

Lecidea jurana"b 

e 

L e c idell a s tigmat I e a@ 

Lempholemma botryowm" 

Lepraria crassissimad 

L, incanad 

.L. sp. (bright green)d 

Lep r oplac a chry s o det ad 

L. xantholytad 

Leptogium lichenoide s" 

L. plicatile" 

Opegrapha calcarea" 

O. cheoallieri" 

O. mougeotii" 

O. persoonii" 

O. saxatilisb 

O. saxicolab 

Petractis clausab 

Physcia adscendensl 

P. caesial 

P. dubiat 

P. nigricanst 

P. orbicularisl 

P. tenellaf 

P. wainioil 

" Caloplacetum heppianae (p. 353) 

b Gyalectetum jenensis (p.355) 

" Dirinetum stenhammariae (p. 356) 

Tenrr YlII-continued 

Phy s conia enter o xanthab 

P. grisear 

P. lruloerulental 

Placynthiurn nigrurn" 

P. subradiatum" 

P, tremniacumb 

Polyblastia albida" 

P. cupularis"" 

P. schraderi" 

Porina chlorotica var. persicinab 

Pr of ob last enin immer s ao " 

P. incrustans" 

P. metzlerin 

P, monticola" 

P. rupestris"b " 

Psorot ichia schaer eri" 

Rhi z o c ar pon umbilic atum" 

Rinodina bischoffii"" 

Sarcogyne regularis" 

Sol enopsor a c andicanso " 

Staurothele caesiao 

S. hlmenogonia" 

S. rtEifuaga" 

S. succedens" 

Synalissa symphoreae 

Thelidium de cipiens" b " 

T. incaz;atunf 

T. papulare" 

T. pyrenophorum" 

Toninia aromaticae 

Verrucaria coeruleao" 

V. dufourii"" 

V. glaucina"" 

V. hochstetteri" 

V. muralis" 

V. nigrescens" 

V. sphinctrina" 

V. oiridula"" 

Xanthoria aureolat 

X. parietinal 

d Leproplacetum chrysodetae (p. 357) 

c Placynthietum nigri (p. 357) 

I Physcietum caesiae (p.360)

352 

a site, (2) successional and competition effects 

, (3) the softness (e.g. the calcium-silica ratio) 

(4) the chemrcal composition of the rock (e.g. 

The associations accepted within this alliance here all occupy distinctive 

microhabitats (Fig. 7) as well as having characteristic floristic compositions 

Coloplocc I um hcppionoe 

Plocynlhielum nigil 

Dtnnelum slenhommonoe 

Gyoleclelum jenensts 

Woler tempororily presenl 

Phtscielum 

coestoe 

Le np ho lem m o bol ryos un - nodum 

Leproplacelum chrysodelae 

Gyaleclelum jenensis 

Frc. 7. Diagrammatic section through a limestone bluff to illustrate the microhabitats 

occupied by the principal lichen communities on limestone. 


studies rrray be able to justify a larger number of associations than is 

accepted here' 

The correct nomenclature of this alliance, like that of two of the marn 

associations treated below, is not entirely clear at the present time' For 

this reason no attempt has been made to typify the names in the rank of 

alliance cited as synonyms above. 

C aloplacetum hePPianae DR. 

Soensk. ocixtsociol. Stiltsk. Hantll. 2, +7 (1925) las "Caloplaca heppiana-Ass."l. 

,,Syn Klem. 

"(Ku 

Klem'; 

'(DR.)" 

"(Gu 

oaria 

Massd ; Lecanor etum dispersae Beschel. 

rts.; ? 

This association, which further study may show does indeed merit 

generally present in such reduced communities. Many lichens which occur 

in this association are, however, small and easily overlooked (particularly 

the pyrenocarpous species; see Table VIII). 

In particularly high-rainfall areas with low sunshine, especially on 

* The nomenclature of this and the Placynthietum nigri (p. 357) remain confused 

and require a very detailed investigation, particularly in view of numerous nonlatinized 

names in the literature (e.g. Kaiser, 1926). Rather than tal

.\ i 

=- 

{: 

..-. 

!: 

O 

o- 

4l 

6: 

c: 

c^ 

.do- O: 

!l 

o. -: 

o 

C: 

!- 

aQ- 

= 

a? 

!: 

G+ 

d\ c 

! ts*' 

g 

Q-> 

a.- 

€-: c. 

.a 

r! 

Cambrian limestones, a 

10. Lichen Commtmities in the British Isles 3-5-5 

i"".[p"a, inclucling C. s 

;r'r;;;; te'mpletonii,"Proto 

Gy alectetum j enensis Klem. 

frequency I'alues]. 

oor in Calopiaca species is 

sses)' Collenta multipartitttnt' 

Solorina saccata and Sqr'ia-

356 P. W. James, D. L. Ilazpksztorth and F. Rose 

chlorotica var. persicina and protob 

an often ovcrlooked but locallv 

probably faithful to this u..o.i, 

ticularly w-ell developed in the lime 

Symond's Yat, but it e 

in south-west E 

Klement (19 Leproplaca xantholyta as a characteristic 

species ofhis C ,oihrio, but no Leirariarp."i..-*.r".it..I 

by him or Wirth (1972); this thus appears to be a 

community than the Leproplacetum chrysodetae. 

as a synonym of the Gyalectetum jenenr-ls rather t 

here. 

wirth (1972) also mentions Dermatocarpon miniatum and, this is also 

znsis in the British Isies although 

shaded facies of the moisturc_ 

etum saxicolae Mot. (Motyka, 

me for this association buf is 

ola is rarely dominant in the British 

Dirinetum stenhammariae (DR.) comb. nov. 

Lecanactinetum stenhamrnriae DR', svensk. .cixtsocior. sattsk. Hanett. 2, 47 

(1 925) fas " Lecanactis stenhammartl Or..,t]. 

The Dirina stenhammari-dominated communities on limestone have many 

lichens in common cetum heppianae buttend to be rather 

poor in placodioid 

C. ochracea) may 

, vertical or almost vertical, 

also preferred. rn its environmental #ll*'*:H;11'JtH: 

unlike the corticolou,s Lecanactiletuy 

l>remneae (p. 309). In so,rthern 

England this association occurs far from natural iimestone outcrops 

church 

on 

walls. Other species e ,red in this .o-,rr,r.ritf 

Isles 

in in. n.i,i.t, 

includ e Dirina 'repanda 

calcarea, 

O. mougeotii and O. subileaata Mediter_ 

ranean or Lusitanian affinities, is, poor in 

species in the British Isles. 

10. Lichen Commurities in the British Isles 357 

Leproplacetum chrysodetae ass. nov. (Table IX) 

This previously unrecognized association is restricted to mocleratcly shaded 

dry underhangs, recesses, cave entrances and sheltered sides of mortarstone 

walls where the substrate is never directly wettcd by rain or watcr 

run-off; presumably the component species obtain their moisture from the 

atmosphere (u'hich is often particularly humid in such habitats). The 

abundance of Lepraria crassissima, L. incana, Leproplaca chrysodeta and 

L. xantholyta characterize this association although the frequencies of 

these four species may vary markedly from recess to recess and all may not 

be present in each site. A further species encountered in this community 

is an apparently undescribed bright green Lepraria which is widespread 

in this habitat in the British Isles; this lichen is probably faithful to the 

Lepr oplac etum c hr y s o det ae. 

As the specialized niche occupied by this association (Fig. 7) is unfavourable 

to most species of its alliance, this community tends to be 

rather poor in species although components of the Gyalectetum jenertsis 

may occur in it occasionally at low cover valucs. 

The Leproplaca-absent b:ut Lepraria-rich Arthopyyenietum conoideae 

Codr. has some affinity with the Leproplacetum chrysodetae but appears 

somelvhat intermediate between the present association and the Gyalectetwn 

jenensis; for this reason it is not treated as identical to either here. In 

Britain Acrocordia conoidea Lepraria communities occur where stands of 

the Gyalectetumjenensis and Leproplacetum chrysodetae adloin one another 

and appear to be of little syntaxonomic importance. 

Placynthietum nigri Klem.* 

Beih. Feddes Refert. 135, 89 (1955) fas "(DR. 1925) Klem."].-Placynthieto- 

Verru,carietum nigrescentis DR., Szensft. acixtsociol. Stillsk. Han.dl. 2, ++ (1925) 

las " P lacynt hium nigrum- V erruc aria nigr escens - Assoziation"]. 

"Synonyms"*: Collematetum crispi-Verrucarietum m.uralis Galle ; Collematetum 

pulposi Kaiser; Collematetum multipartitis DR.; Collematetum tunaeformis 

Alberts. 

This association, under a variety of names, has often been treated as 

forming an alliance distinct from the Aspicilion calcareae (by, for example, 

Klement, 1955; Degelius, 1954; Hawksworth, 1969) but, in view of the 

large number of species it has in common with that alliance, it seems 

preferable to regard it as a distinct association in the same alliance as that 

* See footnote on p. 353. For other synonyms or possible synonyms see Kaiser 

(1926) and Klement (1955). 

.t

3s8 P. W. James, D. L. Hawksworth and F. Rose 

::il'Jl"l;g"!;.,1Y:ffi ,',,,|,X'::;,:;dpracodioidcatoptaca-containing 

The Placynthietum nigii prefers damper situations than the caropracetum 

Tasrn IX, 

Lepl oplac etum chry s ode t ae ass. nov. 

Species Stand 

Acrocordia conoidea 

Caloplaca cirrochroa 

C. heppiana 

C. saxicola 

C atillar ia lenticularis 

C lathroporina calcar ea 

Dirina stenhammari 

Gyalecta jenensis 

Lecanora dispersa 

Lepraria crassissima 

L. incana 

L reen) 

L socleia 

L 

Porina chlorotica var. 

persicina 

Pr otoblas lenia rupestris 

Verrucaria muralis 

V, nigrescens 

Bryophytes 

2 

2 

; 

2 

i 

; 

2 

+ 

2 

+ 

65 

t/ 

J 

+ 

5 

_., 

3_ 

1' Derbvshire, Lathkirt 

.Drre .(431165660): carboniferous rimestone underhang, 

,. ili[3]"f.ri"^,,1,9.1 T : 19:f,^"""*',io%, 25 Aprl 1e7s, D.r..H. 

-8 

-L l- 

.7 

6 

1.- 

1.- 

.) .) 

0.2 

1.1 

')) 

2.2 

1.1 


heppianae but, like it, requires light although it is rather rrrore tolcrant of 

slight shading. This association thus tends to occur in rather less cluickly 

draining microhabitats, such as damp vertical faces, undulating limcstone 

surfaces and slopes where water run-off keeps them moist. Some facies of 

the association are rich in bryophytes whilst others may havc the large 

thalli of Dermatocarpon miniatum (see also p. 356) abundant, but it is 

essentially characterized by the abundance of cyanophilous lichens and 

shade-loving pyrenocarpous species (see Fig. 9). Placynthium nigrum is 

Frc. 9. Placynthietunt nigri on limestone. Species present include: Collemo. 

multipartitum, Placynthium lisrnorense, P. nigrutn, Protoblastenia rupestris, Verrucaria 

dufourii, V. hochstetteri, and. V. splinctrina (Argyllshire: Island of Lismore, 

1.971, P. W. James). 

almost invariably present and often luxuriantly developed in this community; 

one or more Collema species also occur of which the most commonly 

encountered are C. auriculatum, C. crispum and C. cristatum, 

although other members of this genus may be abundant in it in some 

localities (".g. C. multipartitum, C. polycarpon, C. tuniforme and C. 

undulatum); Leptogium lichenoides, saxicolous morphotypcs of Z. tereti.ttsculum 

as well as Psorotichia schaereri, are other regularly occurring cyanophilous 

species. The rare Synalissa symphorea is also probably faithful 

to this association. Of the pyrenocarpous species, Thelidium decipiens, T.

360 P. W. James, D. L. Haz.okszoorth and tr,. Rose 10. Lichen Commwities in the British Isles 

coerulea ar'd V. dufourii are par_ 

. A facies not unlike the Tonini)ttnn 

tia candida is replacecl by T. aromatica 

s recognition at the association level as it is 

n mossy limestone rocks in woodland, a facies 

ouriculatum' C' crispum, 

polyblastia 

Cladonia 1>ocillum, 

t 

ruriher speci ::'""i-Xf,'J^"r1",: 

I-ike the 

ntgri is able to 

extend from 

calcareous walls. In churchyards its difierent ecological ,.Tfrr|.l".T::ll 

e.asily be seen by, for example, comparing the lichen communities on trre 

driest and dampest walls of the church, or those on verticar tombstones 

and around the basal parts of horizontal tops of chest-tombs. similar 

contrasts can be seen in comparing limestone boulders in turf and u,iclc 

expanscs of limestone rock faces. The placynthietum nigri is conspicuouslv 

rarer in churchyards in the low-rainfall areas of East Angria th""'i;:;;;; 

and west England. 

Allied to this community is one sometimes encountered in depressions 

in limestone which often hold water fc r considerable periods of ii-. ancr in 

osum predominates; this may represent a 

is in need of further study it is noi formally 

reated as a "nodum" (see Fig. 7). Free_living 

in such hollows when it is or has just becn 

All. 13. Xonthorion parietinae 

Xanthorion parietinae Ochsn.-see p. 342 for nomenclature. 

Physciehtm ascendentis Frey & Ochsn. 

See p, 344 for nomenclature. 

A community not s association (sec p. 344) occasionally 

occurs on nutrie us rocks urrd *ullr, particularly in 

farmyards. In thi scens, physcia tribaclia and, Ramalina 

duriaei are particularly characteristic of it. 

Physcietum caesiae Mot. 

Bull. int. Acad. pol. Sci. Lett. lCracoaie], ser. B,1924, g43 (1925). 

This association is widespread on nutrient_enriched sites 

perching stones) but, while it is particularly frequent on 

(e.g. birds' 

limestones 

(espccially the Jrorizontal faces on the tops of gravestoncs and concrete 

posts), it is lcss specific to rock type than nutrient availability. In moderately 

pollutecl areas the association is especially well developed

362 P. W. James, D. L. Hawksuorth and F. Rose 

Scotland (e.g. Ben Hope, Ben Lawers, Caenlochan and Glen Clova). The 

community spreads from rock on to adjacent rock debris, bryophytes 

and mica schist-rich soils and thus can be treated as both terricolous ancl 

saxicolous. Detailed lists of the species of this nodum on Ben Lawers have 

been provided by James (1965). On Ben Hope the communities are similar 

but Pannaria hooheri is dominant on rock. Many of the lichens in this 

nodum are extremely rare and restricted to it in the British Isles. The 

following may be mentioned as characteristrc: Belonia russula, Biatorella 

fossarum, Caloplaca stillicidiorum (on mosses), Euopsis granatina, Gyalidea 

fritzei, Pannaria hookeri, Pertusaria glomerata, Placynthium dolichoterum, 

P. pannariellum, Polyblastia cupularis, P. inumbrata, P. scotinospora, P. 

tlteleodes, Protoblastenia siebenhaarina, Sporopodium fuscolutewn, Thelopsis 

melathelia and Thyrea radiata. 

This nodum is apparently distinct from the Aspicilietum oerrucosae 

Frey (see Klement, 1955) although it has a number of species in common 

with it. Its syntaxonomic position is in need of further study but it has 

clear affinities with some communities of alpine habitats in Norway of 

which it probably represents a species-poor facies. 

Rhizocarpon petraeum nodum (Table X) 

Siliceous rocks at the margins of limestone outcrops support a very 

characteristic assemblage of species (Table X) whose presence is indicativc 

of the site being somewhat calcareous. This is essentially a transitional 

nodum occurring chiefly in highland Britain and in which "substrateswitch" 

species arc an important component. Some species of this community 

(".g. Caloplaca flaoocirescens, Buellia alboatra, Rhizocarpon 

petraeum) occur, for example, on granite stones in a stone and calcareous 

mortar u'all in lowland Britain. Species found in this nodum include 

Bacidia sabuletorum, B. umbrina, Caloplaca aurantiaca, Candelariella 

aitellina, Lecanora muralis, Lecidea illita, L. speirea, L. umbonata, Lecidella 

stigmatea, Lithographa tesserata, Polyblastia theleodes, Protoblastenia 

monticola, P. rupestris (not usually as "var. caloa"), Rhizocarpon petraeum 

and Thelidium pyrenophorum. This community is not accorded the status 

of an association here as it is essentially transitional betwcen limestone and 

siliceous rock associations and is usually very limited in extent. 

Ability to recognize this nodum is of considerable importance to ecologists 

as it enables base-rich rocks in essentially siliceous rock areas to 

be recognized and thus indicates sites of potential importance for their 

phanerogamic floras. 

Species 

Acaros\or a glattcocarPa 

Bacidia sabuletorum 

B. anbrina 

Buellia aethalea 

CaloPlaca aurantiaca 

C. citrina 

C andelariella oitellina 

C atil laria lenticul, ar is 

C lathr oPor ina c alc ar e a 

CoIIema cristatum 

C. PolycarPon 

Gyalecta jen'ensis 

H uili a alb o c a er u I e s c ens 

IonasPis ePulotica 

Lecanora crenulata 

L. disPersa 

L. muralis 

Lecidea il.lita 

L. lithoPhila 

L. pelobotryon 

L. speirea 

L. umbonata 

Lecidella scabra 

L. stigmatea 

LithograPha tesserata 

Pertusari.a amara 

P. pseudocorallina 

P lacynthium lis mor en s e 

Polyblastia scotinosPor a 

P. theleotles 

P r ot obl a s t enia monticol a 

P. ruPestris 

Rh i z oc a r Pon ob s cur atum 

R. Petraeum 

Thelidiutn deciPiens 

T. pyrenoPhorum 

TraPeka coarctata 

Verrucat'ia coerulea 

Test,n X. 

Rhixttc arP on Petr aeunt' nodum' 

t-,2 

t, 

+.0 

1.2 

1.0 

L') 

2.2 

1.2 

tC 

1-.L 

1.2 

r.2 

1.2 

2.3 

)-) 

)-) 

l', -r.L 

1.3 

-)- ? 

1,.2 

-L') 

1.2 

J,) 

)-7 

)-) 

+.0 

)-) 

L-') 

1.2 

+.0 

+.0 

1.3 

L) 

)-) 

1.2 

1.3 

z.J 

7.2 

1.3 

1.3 

-J- ) 

1.2 

t2 

),') 

l.z 

Stand 

L2 

L.J 

t.z 

+.2 

+.0 

), ') 

rO 

1.3 

), ') 

), ') 

t.2 

-L) 

1.2 

1.2 

=), ) 

),) 

+.0 

1.3 

f.0 

1.2 

t.2 

- 

4.0 

L) 

- t.r 

+.2 1.2 

1.3 1.3 

+.0 +.2 

ta 

1-.L 

tC 

- 

ta 

tn 

1.3 

r.2 

-L) 

-L) 

1.3 

1.2 

-L)

364 P. W. James, D. L. Ilazpksworth and F. Rose 

'Iasrn X_continued 

Species Stand 

V. glaucintt 

V. hochstetteri 

V. muralis 

V. sphinctrina 

V. airidula 

-)- ', 

1.2 

_L) 

J-.0 

+.0 

)- ') 

_J- ') 

-l? 

-)_ ) 

+,0 

-L) 

+.0 

1. '.) 

-L? 

+.0 

+.2 

1.2 

t) 

1. Sutherland, lnchnadamph, lowcr slopes of 

transition between acid rock u"a ti-".ton., 

e 1961, r.w .J . 

Ramsey (17 1992462): transition beru,ee n 

exposed site, incl. + 10., aspect 270o, 

.w.J. 

ove Lochan an 

st 1.970, p.W.J. 

): exposed sitc, 

Carsaig, near Nuns.pass (l 7/525205); 

ust 1969, p.W.J. 

, Great Close (44/90367g): smalt outcrop 

, 0.5 x 0.5 m, 16 August 1967, p.\N.I: 

centricae Mot. (Motyka, 1926, pp. 219, 226) 

this nodum but this was poorly circumscribe.l 

the non-British Leciclea'nioeiatra as a main 

VI. Siliceous Rock Communities 

have, with the notable exception 

received scant attention in thc 

ever, support more lichen species 

ish Isles. While many communities 

occur, problems of identification of 

survey work undertaken mean that 

ularly tentative. 

t of these communities parallel 

(see p. 304) with the ac{dition of 

rdness and friabilitl, and (3) heavy 

10. Lichen Communilies in the British Isles 365 

In order to draw similar alliances and associations together, the siliceous 

rock communities have been grouped into six broad habitat categories: (A) 

shaded, (B) exposed, (C) nutrient-enriched, (D) mineral-rich, (E) marine 

and maritime, and (F) aquatic. 

All. 14. Leprarion chlorinae 

A. Shaded 

Leprarion chlorinae Smarda & Hadad, in Klika & Hadad, Pffuoda, Bnto 36,253 

(1944).-Cystocoleion nigriWirth, Diss. Bot., Lehre 17,105 (1972). 

An alliance of shaded underhangs and recesses in hard siliceous rocks 

which are sheltered from direct rain; the acid rock counterpart of communities 

in dry bark recesses (pp.306-313) and similar situations on 

limestone (pp. 349-360). Crustose and leprose species predominate in this 

alliance and many of hese are abundantly sorediate; indeed a high 

proportion are unknown fertile. 

A comprehensive key to the lichens of shaded acid rock crevices and 

underhangs in Britain is provided by James (1970) and includes information 

on the distribution of the species. 

Some species-poor communities referable to this alliance are also able 

to occur on upturned tree roots, soil, pebbles in roadside cuttings or in old 

acid woodlands, as well as in the dry overhangs and recesses in rock of 

which they are characteristic. The essentially corticolous Coniocybeturn 

furfuraceae (p. 308) is also able to spread on to rock and dry soil in suitably 

shaded sites and form intergrades with both the Lecideetum lucidae and the 

L. syloicolae. The broad ecological amplitude of the Leprarietum incanae 

(p. 312) includes siliceous rocks on which it can form transitions to the 

Lecideetum lucidae and Racodietum rupestris in particular, 

The Sclerophytetum circumscriptae of recesses in maritime rocks, u'hich 

occupies comparable but more base-rich habitats than the Leprarion 

chlorinae, is discussed separately below (pp. 387-388), while the heavymetal 

requiring Lecanoretum epanorae, which also has an affinity for 

dry crevices, is discussed on p. 383. 

Mention should also be made here of a community of uncertain syntaxonomic 

position which is currently poorly known and thus not recognizecl 

formally here: the Lecidea phaeops-L. taylori nodum. This'is essentially a 

community of damp overhangs oi .*pot.d rocks lvithin sheltered woodland 

sites to which Gyalidea hyalinescens may also be faithful; that it requires 

damp rocks indicates that it should be placed in an alliance othcr than the 

Leprarion chlorinae and may perhaps be close to l\e Aspicilietum lacustris 

(p. 3e1).


Lecideeturn lucidae (Schade) Wirth 

Diss. Bot., Lehre 17, ll (1972).-Biatoretum lucidae Schade, Beih. Feddes Repert. 

76,20 (193+).-Biatoreto-Chaenothecetum Schade, Ber. dlsch. hot. Ges.41, (58) 

(tez+). 

A species-poor and very widespread association of dry recesscs in siliceous 

rocks, also encountered on stonework, gravestones and brick, and often 

consisting only of Lecidea lucida althorgh Lepraria incana may be locally 

important. It is pollution-tolerant and particularly common in moderately 

polluted areas on shaded brickwork. This association shows some tendencv 

to merge into the Micareetum sybicolae (p. 366) and is also allied to both 

the Coniocybetum furfuraceae (p. 308) and the Leprarietum incanae (p. 312), 

both of which can also occur on rock. 

Lecideetum orostheae (Hil.) Wirth 

Diss. Bot., Lehre 17,122 (I972).-Lecanoretum orostheae Hil., Cas. ntir. Mus. 

1927, 9 and 1 5 (1927) las "Association b. Lec anor a orosthea"l. 

This association prefers somewhat better lit sites than other members of 

this alliance and as treated here tends also to be relatively species-rich. It 

is particularly well developed on the andesitic rocks of the Welsh border 

counties. H aematomma oclu oleucun (including var. porphyrium), Lec anor a 

gangaleoides, L. subcarnea, Lecanactis dilleniana and Lecidea orosthea are 

particularly characteristic of this community. Other species commonly 

encountered in it are Catillaria chalybeia, Huilia albocaerulescens, Lecanora 

atra, L. grumosa, L. ntpicola, Opegrapha saxatilis, O. saxicola, Parmelia 

glabratula ssp. fuliginosa and Rhizocerpon geographicum s.I. 

Lepr arietum chlorinae Schade 

Ber. dtsch. bot. Ges. 41, (57) (192+). 

This association is rather rare in Britain and largely confined to the central 

highlands of Scotland. It may be viewed as an upland counterpart of the 

Lecideetum lucidae and rarely includes species other than Lepraria chlorina. 

Micareetum syloicolae ass. nov. (Table XI) 

This previously unrecognized association is closely allied to the Lecideetum 

hrcidae, of which we were first inclined to treat it as a facies, but appears 

sufficiently distinct in both species composition and habitat, preferring 

Species 

Coniocybe furfuracea 

Custocoleus niger 

Ii aem atomma 

Lecidea lucida 


L. membranacea 

Mirarea claoulifera 

L[. Polioides 

M. semiPallens 

M. sylaicola 

OpegraPha gYrocar1a 

O. zonata 

Porina chlorotica 

P. lectissima 

Racodium ruPestre 


o ch r o I eu cum 

Tesln XI. 

Micareetum sYl'aicolae ass' nov' 

1.2 

2.3 

1.2 

2.3 

+.0 

+.0 

7.2 

3.+ 

1.2 

1.2 

t.2 

-l-.0 

L) 

1.2 

i.t 

1.3 

2.3 

1.2 

+.0 

Stands 

+.0 

1.2 

2.3 

+.0 

3.+ 

1"2 

1.2 

367 

1.2 

_ 1.3 

2.3 1.2 

t.2 1.3 

1.2 

2.3 

- 1.3 

7.2 2.3 

l, 

1. Radnorshire, Rhayader, Glam lyn (221940693): rock outcrop in sheltered old 

-'*..af""a, incl. 6b', aspect 23i', 1'0 x 1'0 m, covef 70o/o, 16 Aptil 7976' 

P.W.J. 

2. Islani of lr'Iull, Tobermory, Aros woods, sput Dubh (I7 15095+5): rock outcrop 

in dense old ltagus wood,'incl.90., arpeci135', 1.0 x 1'0 m, cover 600/0,77 

October 1970, P'W.J. 

3. Somerset, Porlock, Horner Combe, Cloutsham (31/898430): rock-outcrop in 

.*'oods, incl.60", aspect 270',0'5 x 0'5 m' cover 95%' 18 July 1969' P'WJ' 

4. W. n*., Upper Loch Torridon, Torridon House (18/868575): rock outcrop by 

*oodland puitt,;,",.t. 100', aspect 235", 1'0 I 1'0 m' cover 90f'u' 12 August 

1966, P.W.J.; tYPe record' 

5. 

Gwynant, near KingsYouthHostel (23/683161) : 

stream, incl. 80", aspect 270", 1'0 x 1'0 m' 

.J. 

6. vn Mair (231647416): sheltered boulder in old 

wood,incl.90",aspect235",1'0x1'0m,cover80ls'16April1965'P'W'J' 

particularly humid recesses (e.g. in 

-Characteristic species of the Mica 

Micarea claztulifera, M. polioides, M' 

incana. It should be noted that th 

is poorly understood in Britain and in need of critical study' 

+.0 

t-7

368 P. W. James, D. L. Hazpksztorth and F. Rose 

Opegr aphetum ltoristico-gyrocarpae Wirth 

H:'_yqlo 1' 195 (1969) .-opegrapha zonata soz. Deger., (/ppsar. (Jnizt. Arsskr. 

1939 (1)' 88 (1939).-0r>egraphetum zonatae wirth, Herzogia 1, 195 (1969) fas 

"Degel. em."]. 

An association of continuously shaded rock underhangs and recesses in 

humid situations but preferring somewhat drier niches than the Raco&ietum 

rupestris. opegrapha gyrocarpa and o. zonata are the most characteristic 

Racodietum rupestris Schade (Table XII) 

This distinctive association consists 

niger andf or Racodium rupestre mix 

incana and/or L. membranacea. Th 

vertical or almost vertical hard si 

situations and recesses which are not subject to direct rain. A considerable 

l. 

2. 

J. 

Species 

Baeomyces rufus 

Cladonia coniocraea 

C. macilenta 

C. squamosa 

Cystocoleus niger 

Diploschistes scruqosus 

Fuscidea cyathoides 

Huilia albocaerulescens 


Lecidea tumida 


L, membranacea 

Ochrolechia androgyna 

Parmelia saxatilis 

Pertusaria corallina 

Racodium rupestre 

S phaer op hor us g lobo s us 

Trapelia coarctata 

Usnea subfloridana 

Tesrn XII. 

Racodietum rupes tr is Sch ade. 

_:___ 

884- 

-_,___ 

-+ 

__ _ _;; 

'_ _!2: 

-- _ -;; 

--) 

Stands 

+5 

Conocephalum conicum - 

Diplophyllumalbicans 

Frullania dilatata 

Hypnum cupressiforme 

Rhacomitriwn 

3 

- 

+ 

3 

- 

3 

heteroslichum 

Scapania umbrosa - 3 

4. Yorkshire, near Goathland, Mallyan Spout Gorge (451824009): sandstone, incl. 

90', aspect 350', 15 x 20 cm, cover 80/6, 29 May 1969, D.L.H. 

-t- Durham, near Cotherstone, High Shipley Wood (45/014204): fine grained 

sandstone, incl. 120", aspect 205", 20 >< 20 cm, cover 80%, 30 May 1969, 

D.L.H. 

6. Cumberland, Buttermere, Scales Wood (35117 - 16-): Borrowdale volcanic 

rocks, incl.96o, aspect 15', 10 x 10 cm, cover 80/o,4 June 1969' D.L.H. 

7. Derbyshire, Holloway, Lea Hurst (+31320560): millstone grit, incl. 95", 

aspcct 90', 2O x 2O cm, cover 95o/o, 5 August 7967, D.L.H. 

8 

Cumberland, Keswick, Castle Head Wood (35/269226)'. Bonowdale volcanic 

rocks, incl.88", aspect 250',20 X 15 cm, cover 80/6,3 June 1969, D'L.H. 

: J 

+ 5 

+ 

+ 

: J 

J 

5 

J 

; :-L 

I 

+ 

+ 

8 

i 2 

(t 

+ 

+ 

5

370 P. W. ./ames, D. L. Hawhsworth and F. Rose 

be present in it proclucing stands transitional to the mainly corticolous 

Coniocybetttm furfuraceae (p. 308). 

Mention should also be made here of a particularly interesting community 

of vertical rock faces in old coniferous r,voodland which is encountered 

rarely in central Scotland (e.g. Glen Strathfarrar) ancl comprises 

Arthonia arthonioides, Cystocoleus niger, Diploschistes scruposus and 

Haematomma ochroleucum. The syntaxonomy of this community requires 

further study but it may prove to represent an undescribed association. 

All. 15. Lecideion turnidae 

B. Exposed 

Lecideion tumidae Wirth, Diss. Bot., Lehre 17, 131 (1972). 

This species-diverse alliance was described by Wirth (1972) to accommodate 

communities on exposed siliceous rocks, boulder scree and heathland 

pebbles in inland sites. The communities are dominated by crustose 

lichens of which Fuscidea cyathoides, Huilia crustulata, Lecidea lithophila, 

L. tumida, and Rhizocarpon geographicum aggr. are particularly characteristic. 

Stereocaulon dactylophyllurn and S. eztolutum are also important 

species in some associations of the alliance of which three are here accepted 

as llritish. The alliance, poorly understood in this country, appears to 

have very close affinities with species-poor facies of both the Parmelieturn 

glomelliferae and the Ilmbilicarion cylindricae; the relationship of the 

Pertusarietum corallinae in particular merits detailed investigation. 

Huilietum crustulatae (Klem.) comb. nov. 

Leci.deetum crustulatae Klem., Ber. bayer. bot. Ges.28,25+ (1950) fas "LecanoretuTn 

coarctatae Duvrgn. 1939 p.p,"], basionym. 

f'his is primarily an association of small, more or less firmly anchored 

pebblcs or stones in open tracts of heathland, but it can also occur on 

larger outcrops and boulders. The characteristic species are Baeomyces 

rufus, Huilia macrocarpa, H. crustulata, Lecanora polytropa, Lecidea 

erratica, L. plana (chiefly in Scotland), L. tumida, Rhizocarpon obscuraturt 

and sometimes Trapelia coarctata s.s. Adjacent terricolous communities 

are frequently rich in the more widespread species of Cladonia as well as 

Lecidea granulosa and L. uliginosa. Communities dominated by Baeomyces 

rufus and Trapelia coarctata s, lat. on shaded rocks and stones are treated 


hereasaspecies-poorfaciesofthiswidespreadmoorlandassociationwhich 

i.q,-,i.". particularly humid sites' 

Le c i d e etum kthoPhil ae Wirth 

Herzogia 1,202 (1969)' 

P er tus ar ietum c or allinae F t eY 

Mitt. naturf . Ges. Bern 6, 163 (1'922) las "Pertusaria corall'ina-Lss'"1' 

This is a widespread species-rich community of well lit siliceous rock 

outcrops, boulders and .rvalls in sites which are not nutrient-enriched' 

ImportantcomponentspeciesofthisassociationintheBritishlsles 

include Cladonia cocciferi, C. squanosa, Diploschistes scrupostts, Fuscidea' 

cyathoides, Lecanora iadia, L. 1>olytropl, Lecidea leucophaea' L' tunLida' 

iarmelia glabratula ssp. fuli[inisa, p. saxatilis, Pertusaria corallina, 

P. deaba\a, P. tactea, P' pseudocorallina, Rhizocarpon geographicum' 

R. lecanorinum, Srhaere,ia rlnereort'tfa and Umbilicaria polyphylla' 

The Pertusarietum corallinae tends to prefer moister sites than the 

umbilicarietum cylindricae and nutrient-poorer sites than the Lecanoretum 

sordidae, preferr:i.g, for example, vertical rather than horizontal rock 

surfaces and walls. 

All. 16. Pseud.eoernion Jurfuteceae 

Pseudeaernionfurfuraceae (Barkm.) P' James et al'; see p' 334 for nomenclature' 

371

372 P. W. James, D. L. Hazlkszpoytlt and F. Rose 

P s eudeo ernietum furfur aceae (Hil. ) Kalb 

See p. 335 for nomenclature and composition. 

This primarily corticolous association is widespread as a specics-1.roor 

variant (see p. 335) on hard acid siliceous rocks and walls subject to mocleratc 

air pollution. The Pseudeoernietum furfuraceae also occurs in the llritish 

Isles on walls and rock debris; in this case the association appears to 

represent a seral stage giving \\ray to associations of the Lecideion tumidae 

or the Umbilicarietum cylindric ae. 

Atl. 17. Rhizocarpion alpicolae 

Rhizocarpion alpicolae Frey, Ber. Geobot. Inst. Riibel 1932,46 (1933). 

The Rhizocarpion alpicolae is an arctic-alpine alliance of nutrient-poor 

siliceous rocks. Due to the relatively mild oceanic climatic conditions, the 

alliance seems to be poorly represented in the British Isles and mainly 

confined to the summits of mountains in Scotland and northern England. 

The two associations recognized here are characlerized by a variety of 

crustose species of which Fuscidea hochiana and Rhizocarpon a.lpicola are 

the respective diagnostic components. Crustose lichen elements of the 

Umbilicarion cylindricae are almost invariably present and macrolichens of 

the same alliance may also be reprcsented. 

This alliance is currently poorly understood in tsritain due mainly to the 

lack of information on the lichen flora of the summits of many Scottish 

mountains. The follovving two associations are tentatively delimitccl here 

as a guide to further study of this interesting alliance. 

Fuscideetum hochianae (Wirth) comb. nov. 

Lecideetum kochianae Wirth, Diss. Bot., Lehre 17, 190 (1972) [as "Ullrich et 

Wirth 1969 em. et nom. nov."] ; basionym.-Lecideetum hochiano-aggregatilis 

Ullrich & Wirth, Herzogia 1, 199 (1969) [non Tobol. 1961]. 

The name Fuscideetum hochianae is applied to an association dominated by 

Fuscidea kochiana and including Lecanora atra, L. intricata (including var. 

soral'ifera), L. polytropa, Lecidea leucophaea, L. lithophila, L. pantherina, 

L. tenebrosa, Parmelia incuroa, Pertusaria corallina, P. pseudocorallina and 

Rhizocarpon geographicum. Species of Umbilicana, such as LI . polyphylla, 

LI . polyrrhiza and U. torrefacta, together with Lasallia pustulata, are 

sometimes also represented but are confined to the apices of slightly 

nutrient-enriched erratics. 

Parmelietum omPhalodis' 

Rhi z oc ar P etum alPic olae F rcY 

10. Lichen Communities in the Btitish Isles 

Verh. naturf. Ges. Basel 35, 310 (1923)'-Rhizocarpetum geolrap.hicae Frey' 

VrriX. Cro1ot. Inst' Riibel4,230ltbZ; ias "Rhizocarpon geographicum-Ass'"1' 

and U. torrefacta. 

In wetter sites characteristic of late snow lie, Rhizocarpott badioatrum 

373

37+ P. W. James, D. L. Hauthsworth and tr'. Rose 

All. 18. Urnbilicarion cylindricae 

(Irnltilicarton cylindricae Frcy, Ber. Geobot. Inst. Riibel lg3z, +0 (1933). Lrnbiti. 

carion hirsutae Follm., Hess. flor. Briefe 2,25 (1973). 

This alliance is characterizedby many species which are strictly montant 

in the British Isles, includrng cetraria commixta, c. hepatizon, corniculariu 

facics of this alliance. 

Many crustose species enter the associations of this alliance of which 

The two associations recognized here are distinguished by both their 

habitats and species composition. 

Parmelietum omphalodis DR. 

Ahad' Abhandl. uppsalal92L,76+ (1921) fnot seen]; see Derzenne-van Halurvyn 

(1976) for later usages. 

t.E,-13 

h:(tt 

't 

!:. t 

di( 

C3 

L 

;o OO 

o 

d 

E 

! 

O! 

tu L 

o= 

^ 

o 'tr* 

\N 

rb[ 

ad 

o 

-: a. 

ttr: 

"s S-o 

:, 

\i 

O€ 

-c ."q 

.! Q., 

fr. 6


The association is often rich in bryophytes of which Andraea rothii, 

A. rupestris (syn. l. petrophila), C),nodontium polycarpum (rare), Hypnunt 

cupressiforme, Isothecium tnyosuroides, Orthotrichum anomalum, Rhacomitriurnfasciculare 

and R. heterostichumrnay be considered as characteristic" 

The Parmelietum omphalodrs occurs at lower altitudes and latitudes than 

the Umbilicarietum cylindricae often occurring even in or near coastal 

areas in western parts of the British Isles. At higher altitudes it tends to 

grade into the Umbilicarietum cylindricae and species such as Cornicularict 

normoerica, Rhizocarpon lecanorinum, R. polycarpon, Sphaerophorut 

tragilis, Umbilicaria polyphylla and U. polyrrhiza become more abundant" 

As a rule the Parmelietum omphalodzs prefers more sheltered sites than the 

(J mbilic ar i e tum c y lindr i c ae. 

Klement (1955) treated Du Rietz's name Parntelion omphaloclis as a 

synonym of the (Imbilicarion cylindt icae reserving a homonym of the 

latter name for a different, more upland, community including, for 

example, Hl,pogymnia intestiniformes. The usage adopted herc follows that 

of Wirth (1972). 

(lmbilic ariet am cylindric ae (Frey) Frey 

Ber. Geobot. Inst. Rilbel 1932, +0 (1933). Gyrophoretum cylindricae Frey, Mitt. 

naturf. Ges. Bern 6, 168 (1922) las "Gyrophora cylindrica-Ass."l.-Umbili- 

carietum deustae Frey, Ber. Geobot. Init. Riibel 1932,49 (1933). 

The Umbilicarieh,tm cylindricae is a more upland and more light-demanding 

counterpart of the Parmelietum omphalodis characterized by species typical 

of the alliance (p.374). Both associations may occur in very close proximity 

to one another and the relative abundance of the characteristic species may 

vary considerably in different sites depending on both geographical 

location and altitude (particularly as its important components are limited 

climaticallv in the British Isles). T'his association is optimally developed 

on the uppermost slopes of mountains in the Scottish Highlands where it 

represents a seral stage leading to the Rhizocarpetum alpicolae, an association 

with a very limited distribution in the British Isles. 

The synsystematics of the Llmbilicarietum cylindricae are poorly understood 

in Britain but our observations suggest that they are very complex. 

Preliminary studies indicate that there are sevcral distinctive noda (indicated 

below), some of which may be referable to the Parmelietum omphalodis, 

and others of which may well prove to merit recognition as separate 

associations when thoroughly investigated. 

1. I)ominatedby Fuscidea tenebrica with F. cyathoid,es and Rhizocarpon 

geogra\hicum ^s 

?rp.."a mounta 

I,ake District an 

^- 

2. A shadY a 


k.ro*n in Britain only from Scotland 

acid, nutrient-Poor rock' 

c of sunnY rocks in 

rlY abunclant in the 

Fuscidea toenlaYum' 

and al"vays found on 

*-1.' oo-itrated by Fuscidea cyathoides but including Lecidea leucophaea, 

L. lithoph.ita, L. pantheTina, Pertusaria corallina and Rhizocarpon ge}- 

/rat;ri* ugg.. (oft".r R. riparium) as characteristic associates. This 

'rroarr- tends to occur at lower altitudes and latitudes than the preccding 

i*o .roau and is particularly well developed in the Southern Pennines and 

peak District on;illstone grit rocks. This nodum is close to the Parmelietum 

omphalodisbut is placed heie tentatively as it sometimes includes LlmltiLicaria 

polyphylta, U. polyrrhiza or (J. torrefacta. 

' +: ifacies on mineral-rich rocks often in rathcr moist situations as in 

shallow valleys or near mountain lakes dominated by Lecidea lithophilabt 

including L.iapicida and. L. leucophaea; Alectoria nig icans and Cornicularia 

aculeata arc fiequent associates on mosses in such communities. This 

facies has a cleai affinity with the Acarosporetum sinopit:ae (p. 383) but is 

poor in species restricted to mineral-rich sites while including many 

mineral-tolerant ones' 

5. A sun-loving markeclly wesrern community particularly well developed 

in the Rhinog mountains in wales dominated by Lecanora mauroides and 

Rhizocarpon geographiatm but including Lecidea pantlterina and L. 

tenebrosa at high frcqtrencies' 

6. The Umbilicar'ia deusta-dominated nodum treatcd as a distinct 

association by many authors (the (lmbilicarietum deustae lirey, see above) 

which is well developed by the sides of upland mountain streams. 

7. The very high altitude (lmbilicaria hyperborea nodum' 

8. The Umbitiiaria crustulosa-dominated nocr,um of almost vertical 

south-facing, hard volcanic rocks found on the Langdale Pikes in the Lake 

District (see Brightman, L962' for lists of associatcs) 

The ,,typical'l Llmbilirarietum cylindricae is taken here to include high 

fr.qt,,"..i". of Llmbiticaria cylindrica, (l' polyphylla, (l' p,ol1n'rhiza' LI' 

proioscidea ancl/or LI . totre.facta. 'Ihis nodum has a particular prcference 

?or well lit rather course-giained rocks in mountainous areas (particularly 

granite) with Cornicularii normoerica, PserLdephebe pultescenr and the other 

tacrolich".rs mentioned as characteristic of the alliance on p.374 occurring 

in it. Associated bryophytes include Andraea rupestris, Grimmia doniana, 

G. trichophylla, Gymnctmilrioz spp., Hedztigia ciliata, Ptychomitriun 

polyphyllttmi Rhoromit",hLm fasciculaye and R. heterosticlntm var. heterostichum.

378 P. IA. James, D. L. Hawksworth and F. Rose 

All. f9. Pqrrnelion conspersae 

C. Nutrient-enriched 

Parmelion coilspersae Hadad, r.n Klika & Hadad, Pfiroda, Brno 36, 25+ (19+4), 

emend. Wirth, Diss. Bot., Lehre 17, 131 (1972).-Parmelion saxatilis Klem., 

Ber.bayer.bot.Ges.28,257 (1950).-Acarosl>orionfuscataeKlem.,Ber.bayer.hot. 

Ges. 28, 257 (1950). 

The Parmelion conspersae comprises associations of well lit and slightly to 

markedly nutrient-enriched siliceous rocks. It can be considered as the 

acid rock counterpart of the Xanthorion parietinae, dilTering from that 

alliance in too many species to be treated as part of the same alliance. Somc 

elements of the Pal.rmilion conspersae are rt.il ..p....nted in the terrestrial 

zone in coastal areas (Fletch er , 197 3b) and there is thus some affinity r'vith 

the Ramalinehtm scopttlar"es (see p. 386). 

C ande kLri e lletum c or al li z ae Mass6 

V ege tatio 12, 17 3 (1964). 

Essentially an association of nutrient-enriched siliceous rocks such as 

birds' perching stoncs, the Candelarielletum corallizae is frequent in 

suitable sitcs in both coastal and upland parts of the llritish Isles. 'l-he 

characteristic spccies of this community include Acarospctra fuscata, 

Anaptychia fusca, Aspicilia caesictcinerea, Buellia cdnescens, B. punctata, 

Candelariella coralliza, C. aitellina, Lecanora muralis, Physcia caesia, P. 

dubia (especially on gravestones in eastern and ccntral England), P. 

tribacia, P. wainioi, Ramalina polymorpha, R. subfarinacea, R'inodhm 

ntbexigua, Xanth.oria candelaria and X. parietina. On the sea-shore, 

additional species entering the association include Aspicilia leprosescens, 

Caloplaca sp. (undescribed), C. xerntculifera, Lecanora poliophaea and 

Parmelia britannica as well as the three rare spccies Calol>laca scopularis, 

Candelariella arctica and Lecanora straminea. Lecanora fugiens and the 

rarer and related L. andrewii may also belong here; Physcia subobscura 

and Verrucaria fusconigrescens rrlay be locally abundant also. 

In our view the relationship between the Candelarielletum corallizae 

and the Physcietum caesiae (see p. 360) is in need of a critical re-investigation. 

Further study may also indicate that the sea-shore facies of this 

association is better subsumed under the Ramalinetum scopularis. 

10. I'ichen Commrtnities in the British Isles 379 

Lecanoretum sordidae Hil' (Table XIII) 

e as. ruirotl. Mus. 1923, + (1924) fas "asociace L.ecanor,t sordida")' Lecanovetum 

i"jl"irc i,"th, .Drj.s. Bot., Lehre 17, 1.66 (1972) las "Hititzer t925"1. 

Although the Lecanoretttm sordidae is accep 

Wirth (tOZZ1, we are not entirely convinced 

from the Parmelietum glomelliferae to merit a 

difference between these two communities is 

lr* ,i.tr.r, in terms of both species number and cover, in crustose lichens' 

Soecies which are characteristic 

fuscata, Buellia stellulata, Cande 

Huilia alhocaerulescens, I'asallia 

grumos(t (chieflY confined to Scotl 

insularis (parasitic on Lecanora 

Ochrolechia parella, Parmelia cott 

Species 

Acarospora .fuscata 

Aspicilia caesiociner ea 

l.rP. 

Bacidia umbrina 

Buellia stellulata 

C andel ariella aitellina 

Catillaria chalybeia 

Diploschistes scruqosus 

Lasallia pustulata 

Lecnnora atra 

L. badia 

L. gangaleoides 

L. grumosa 

L. intricata 

L. polytropa 

L. rupicola 

Lecidea otosthea 

L. sulplrurea 

L. tumida 

Ochrolechia Parella 

Tasrt XIII. 

L ec anor eturtt s or didae Hil. 

-i.1 

t) 

7.2 

r.2 

7.2 

1..2 

r.2 

1.2 

1.3 

1) 

1.+ 

J.J 

t') 

1.+ 

r.2 

1.2 

1.2 

1.2 

1.2 

1.3 

1.0 

r.2 

2.3 

-r-.0 

7.2 

1.2 

Stands 

.l 

L,) 

+.0 

1.2 

2.3 

1.2 

1.2 

2.3 

I.2 

-L) 

2.2 

1.2 

1.2 

- 

'_' 

7.2 

*_, 

+.0 7"2 

2.3 1.2 

7.2 

- 

1.2 

\') 

+.1 1.+ 

),) 

_ 2.3 

- +.0 

1.2 1.4 

1.3 2.3 

1.2 

2.3 1.3 

+.2 1.2 

- 1.2

380 P. W. James, D. L. Hauthszoorth and F. Rose 

Species 

Parmelia glabratula ssp. 

.fuliginosa 

P. conspersa 

P. oerruculifera 

P er tus aria p s eudoc or allina 

Rhi zocarpon g eogr aphicum 

R. ohscuratum 

R. viridiatrum 

Tanrr XIII-continued 

|,) 

1.2 

1., 

1.2 

Stands 

.) 

2.3 

1.3 

7.2 

+.0 

t) 

2.3 

+.0 

3.2 

+.0 

1.2 

1' Radnor, New Radnor, stanner Rocks (32/2625g4): rock outcrop (andesite), 

incl.45', aspect SW, 1'0 r 1.0 m, cover gsyo, 11 Aprll1976, p.W.J. a.,a i. 

Woods. 

2. shropshire, church stoke, Roundton (32129194g): rock outcrop (andesite), 

incl- 30', aspect S, 1.0 x 1.0 m, cover 9g(%, 13 April 79Z6, p.W.J.' 

3. Radnor, Llandrindod wells, above shakey Bridge, cefnilys (szlotlot+), 

rock outcrop, slight shade, incl. 20., aspeci W, 1:0'x 1.0 m, cover 90fi, 

11 April 1976, P.W.J. and R. Woods. 

4. Montgomervshire, welshpool, criggion, Breidden Hi]J (33129-14-): large 

boulder on sunny hillside, incl. c.20', aspect Nw, 1.0 x'1.0 -, cover 100o/u, 

12 Aprll1963, P.W.J. 

5 Kirkcudbrightshire, Dalbeattie, Moyl peninsula (251g30526): Iarge boulder in 

sunny situatio': incl- 10', aspect s, 1.5 x 1.5 m, cover go%,2\ Aprrr 1976, 

P.W.J.and P. Topham. 

P. xerruculifet,a, Pertusaria flatticans, p. pseudocorallina, Rhizocarpon 

geographicum aggr., R. oh'idiatrum and Rinoditta atrocinerea. In inlancl sites 

in the British Isles the Lecanoretum sordidae is well developed on andesitic 

outcrops in the West Midlands. 

In addition to the strong affinity of this association with the parmelierum 

glomelliferae, it also appears to be allied to a crustose lichen-dominated 

facies of the Ramalinetum scopularls on coastal rocks where, in addition to 

the species listed above, the following exclusively maritime species occur 

in it: Diploschistes caesiophmbeus, Lecidella'subincongrua) pertusaria 

c e ut h o c ar p oi de s and Rhi z oc ar p on c on s tr t c tum. 

Parmelietum glomell'iferae Hil. (Table XIV) 

eas. nrirod. Mus. 1923,7 (1924) fas ,,parmelia glomellifera. asociaci,,]._ 

[]mbil:icari*um pustulatae rlil., prislia 3, 16 ('rgzs) fas "Asociace Lrmbilicaria 

prstulata"l.-Lasallietum pustulata.e (IIil.) wirth,'Drss. Bot., Lehre 17, rsz 

(1972)--Pa,neliehtm isidiotylae Frey,'in Frey & ochsner, Araernia 2, 6g (1926). 

1.2 

1.2 

+.0 

1.3 

3.2 

1,2 

1.2 

+.0 

10. Liclrcn Communities in the British Isles 381 

-Parmelietum conspersae H11., Preslia 3, 16 (1925) [as "asociace Parmelitt conspersa")' 

The Parmelietum glomellifer ae is treated here in a broad sense to include 

communities of nutrient-enriched rocks dominated by species of Parmelia 

and Llmbilicaria s.l. The Parmelietum conspersae ar'd (Jmbilicarietunt 

pustulatae have frequently been maintained as distinct entities by continental 

authors but as they commonly appear to intergrade in the British 

Species 

Acarospora fuscata 

C andelariella oitellina 

Cladonia coccifera 

Fuscidea cyathoides 

Lasallia pustulata 

Lecanora polytropa 

L. rupicola 

Lecidea sulphurea 

Parrnelia conspersa 

P. glabratula ssp. fuliginos a 

P. loxodes 

P. mottgeotii 

P. omphalodes 

P. saxatilis 

Rhizoc arpon g eogr aphiamt aggr. 

Trapelia coarctala 

Umbilic aria polyrrhiz a 

Xanthoria candelaria 

T,qsln XIV. 

P an n e lietum g lo me I lif e r ae Hil. 

Stands 

1. South Devonshire, Dartmoor, Harford (201642601): granite blocks in pasture, 

2 

4 

5. 

23 

22 

-1 

23 

-8 

22 

6+ 

-1 

6- 

47 

c 

22 

,, 

_J 

{ level, 10 x 10 cm, cover 95o/o,3 April 1969, D.L.H. 

South Devonshire, Dartmoor, near Wistman's Wood (20/613768): granite 

boulder used as bird perch, uneven, 20 x 20 cm, cover 909/0, 15 September 

1969, D.L.H. 

South Devonshire, Dartmoor, Rippon Tot (2017487 57): gtanite boulder in 

clatter, incl. 160', aspect45', 20 x 20 cm, cover 80%,30August 1976,D.L.H. 

South Devonshire, Dartmoor, Sharp Tor (201686731): granite boulder in 

heathland, f level, 20 x 20 cm, cover 75o4,29 JuJy 1974, D.L.H. 

South Devonshire, Dartmoor, Crockern Tor (2016167 57): granite boulder in 

clatter near summit, incl. 140', aspect 165', 20 x 2Q cm, cover 85%,, 15 September 

1969, D.L.H. 

.) 

.J 

2t 

+- 

-+ 

+l 

a 

a 

5+ 

JJ 

6- 

-.) 

I2 

23 

-5 

c 

1 

2 

2 

; 1 

1 

7 

.) 

5 

.) 

+ 

-l 

2 

J

382 P. W. James, D. L. Hawhszaorth and F. Rose 

Isles they are trcated as a single association here 

earliest available name we have been able to 

glomelliferae. 

and subsumed uncler thc 

locate-the Parmelietum 

The characteristic species of this community in h Isles arc 

Acarospora .fuscata, Candelariella aitellina, Ctaionia C. pityrea, 

C. squamosa, Lasallia pusttrlatl, Lecanora polytropa, britannica, 

P. cottspersa, P. disjuncta, p. loxotles, p. mougeotii, p. p. sttlcata, 

P' oerruculifera, Traperia ornata, umbiticaia deusta and L,. joerrhiza. 

A very large numbcr of other species may occasionally enter the isociation, 

particularly elements of the parmelietum ompfutlodis and. pseudeaernietum 

furfuraceae; affinities with the Ramar'inetum scopuraris (p. 3s6) are arso 

marked. The relations ip of the present association to the Lecanot,et.um. 

sordidae is discussed under the latier community (p. 3g0). 

All. 20. Xanthorion parietinae 

Xanthorion parietinae Ochsn. See p. 342 for nomenclature, 

Plty scietum caestae Mot. 

See p. 360 for composition and nomenclature. 

This association, characteristic of extremery nutrient-enrichecl sitcs, can 

occur on suitably modified siliceous rocks, especially near coloniar nesting 

sites of birds, as well as on limestones, man-ma re substrates and, rarely, 

trees. 

All. 21. Acarosporion sinopicae 

D. Mineral-rich 

Acarosporion sinopicae Wirth, Diss. Bot., Lehre 17, 131 (1972); type: Acaro_ 

s? or e tum s inopic ae Hil. 

Tliis distinctive alliance. was introduced by wirth (1972) for associations 

restricted to rocks rich in heavy metarr. fh. two associations recognized 

here are. rather specialized.and fiequently contain several species ..st.i.t.a 

to metal-rich rocks. In Britain they occur (1) on spoil tipJ rro- otd -in. 

workings for sopper, lead, silvei ancl associatei metals, fi; on .'"ntt* 

contaminated by heavy metars, principaily lead derived fro-'cu, exhausts 

or particulate fall-out from smelters, 1:) on naturally occurring rrretar-rich 


rock outcrops, and (4) occasionally in the vicinity of, or even on, rusted 

iron rails, worked lead (as in stained-glass windows), or in areas affected 

by water run-off from corrugated iron roofing. The thalli of several 

crustose species characteristic of this alliance are often wholly or partially 

rust red in colour ("oxydated"; see Chapter 2). 

A review of heavy metal tolerance in lichens is provided by James (1973). 

Ac ar o spor etum sinoPic ae HtL 

eas. nrirod. Mus. 1923,8 (192+) las "Acarospora sinopica-asociace"]. 

Characteristic species of this association in Britain include Acarospora 

sinopica, A. smaragdula (including var.lesdain'ii), Bacidiaumbrina, Candelariella 

oitellina, Diploschistes sct,uposxts, Huilia macrocarpa (as "f . oxydata"), 

Lecanora intricatavar. sorakfera, L. polytropa, L. sttbaurea, Lecidea atrata, 

L. lapicida (as "f. oxydata"), L. pantherina, L. silacea (confined to upland 

sites), R/zzzocarpon obscuratum, R. oederi, Stereocaulon nanodes, S. pileatum 

and Toninia leucophaeopses (upland sites only). Other species of. Stereocaulon 

(5. dactylophyllum, S. delisei, S. eoolutum and S. z,esuz;ianum) may 

also be present. In areas subject to moderate to severe sulphur dioxide 

pollution Lecanora conizaeoides enters this community, sometimes becoming 

an important component of it; in such sites the association becomes 

species-poor. 

Lecanora subaurea is a very significant member of this association in the 

southern Pennines (Earland-Bennett, 1975). 

Lecanorehtm epanor ae Wirth 

Diss. Bot., Lehre 17,173 (1972). 

This association is closely allied to the Acarosporetum sinopicaebut tends to 

prefer more sheltered, dry situations, being found particularly in dry 

crevices of mineral-rich acid rocks or on the more sheltered sides of old 

walls. The community, which is rather species-poor, tends to be dominated 

by Lecanora epanora. Other commonly associated species are Lepraria 

incana aggr., L. membranacea aggr. and Rhizocarpon obscuratum. Details of 

the ecology and British distribution of Lecanora epanora are given by 

Earland-Bennett (1975). The occasional presence ol Lecanora subaurea in 

the Lecanoreturn epanorae is indicative of the close relationship of this 

association with the Ac ar o spor etum sinopicae. 

Hilitzer (192+) regarded Lecanora epanora as an important component of 

the Acarosporetum sinopicae but his material was most probably I. 

suhaurea.

334 P 

E. 

Caloplacetum marinae DR. 

W. James, D. L. Hawksworth and tr-. I?ose 

Marine and Maritiftie Cornrrtunities 

saensk. acixtstciol. stillsh. rlantll.2, s0 (192s) las "Caktplaca marina-Lss.,'f. 

'r'he caloplacetum marinae is the characteristic association of the sub- 

10. I.ichen Communities t'.n the British Isles 38s 

Frc. 11. Caloplacetunt rnarinae on maritime siliceous rocks. Predominant species: 

Caloplaca marina, C. thallincola and Verrucari,a mttura (Mid-Ebudes: Island of 

Mull, Ross of Mull, Carsaig Bay.1972, P. W. James). 

C. oerruculifera. Lecanora actophila and L. helicopis are faithful to the 

association in the British Isles, the former tending to prefer more sunny, 

well lit situations. Verrucaria maura is often present (e.g. Fig. 11), 

espccially on more sheltered shores where it is often overgrown by 

Caloplaca thallincola. In northern and some western areas Arthonia 

phaeobaea and Lecania aipospila also form part of this association and may 

become locally abundant. Catillaria chalybeia and Lecania erysibe are 

often common although these species, unlike the othcrs mentioned above, 

are by no means restricted to coastal rocks. Lichina confinis, occurring in 

the lowest part of the mesic-supralittoral zone, forms a link with the 

Verrucarietum maurae; similarly Xanthoria parietina, characteristic of the 

submesic-supralittoral, interconnects with the Ramalinetum scopularis 

association. 

A more nutrient-cnriched facies of this association, commonly including 

Aspicilia leprosescens, Caloplaca "êrruculifera, Lecanora poliophaea, 

Rinodina subexigua and the alga Prasiola quadrata occurs on birds' perching 

rocks along the shore or near nesting sites. The rare Caloplaca scopularis, 

Candelariella arctica and Lecanora straminea may also occur in this 

community. The relationship between this facies ancl the Candelarielletun 

corallizae is noted on p. 378,


Ramalinetum s copul ar i s Klem. 

Beih. Feddes Repert. 135, 68 (1955) fas "(DR. 1925) Klem."].-R amalina scopul_ 

aris-Anaptychiafusca Ass. DR., Saenshbot. Tidshr.19, 333 (1925), nom. inoal._- 

Ramalina scopularis-Lecanora atra-Rhizocarpon constrictwn-Ass. DR., soensk 

bot. Tidshr.19, 333 (1925), nom. inoal.-Ramalbrctum sili.quosae Follm., phiilipia 

2, 8 (1973) fas "(DR.)"].-Lecanoretum atrae Massd, Reaue bryol. lichdn.34,8gt) 

( 1e66). 

The characteristic association of the xeric-supralittoral (grey) zone of 

rocky shores in thc British Isles isthe Ramalinetum scopularis (Fig. 12). A 

species-poor facies of this association may also occasionally be encountered 

on walls of churches, ancient monuments and stone walls or rock outcrops 

in inland sites subject to maritime influence, as for instance throughout 

most of Devonshire and on Avebury Circle and Stonehenge in Wiltshire. 

This community is exceptionally rich in species (see Fletcher, 1975a) ancl 

occupies that part of the sea-shore where moisture derived from the sca 

and soil from the terrestrial environment are minimal. Amongst thc 

characteristic species of this community are Acarospora atrata*, Anaptychia 

fuscax, A. mamilla.ta*, Buellia co.nescens, B. stellulata, Caloplaca ferruginea, 

Frc:.1.2. Rannlinetutttsr:opularisonrnaritimerockssiliceous.Speciespresentinclude 

Anaptychia.fttsca, Ochrolechiaparella, Pnrtneliareticulata, P. saxatilis and Rantalina 

siliquosa (Nlid-Ebudes: Island of lona, 1972,P. W. James). 

* Species predominantly maritimc in the British Isles. 


Diploschistes caesioplumlrcus*, Huilia albocaerulescens, Lecanora atra, 

1,. fugiensx, L. gangaleoides, Lecidea diducens (on quartzite), L. sulphurea, 

L. tumida, Lecidella subincongrua*, Parmelia delisei*, P. glabratuLlr ssp. 

ful.iginosa, P. Pullax, P. loxodes*, P. aerruculifera (syn. P. isidiotyla), 

Pertusaria'pseudocorallina, Physcia subobscurax, Ramalina cuspidata*, 

R. siliEtosa*, R. subfarinacea*, Rhizocarpon constrictum*, R. geograplticum 

aggr., R. obscu,ratum, Rinodina atrocinerea, R. luridescensx, Verruraria 

fusconigrescens* 

and Xanthoria parietina. This association is, howet'er, very 

variable and other species may be very important components of it locallv, 

for example, Buellia aethalea, B. subdisciformis*, B. xerruculosa, Fuscidea 

cyathoides, F. tenebrica, Lecanora rupicola, Lecidea tenelvosa, Perhtsaria 

chiodectonoides, P. ceuthocarpoidesx, P. monogona and Rinodina confragosa*. 

A wetter and more sheltered facies of the Ramalinetum scopularls r.r,hich 

is optimally developed on friable rocks includes Acrocordia salweyi, 

Bacidia scopuLicola*, Enterographa hutchinsiae, Lecania mtpicola*, Lecanora 

dispersa, Lecidella subincongrua*, Opegrapha conJluens, O. gyrocarpa, O. 

lithyrga, O. zonata, Porina chlorotica, P. curnowii*, Solenopsora holophaea*, 

S. aulturiensis*, Toninia aromatica, T. mesoidea*, Verrtrcatia internigrescens* 

aod V. 1>rominulax. 

Specics characteristic of the Lobarion, for example I'obaria la.etez'irens, 

Neplvoma laexigatum, Pannaria microphylla, Parmeliella plumbea and 

Sticta canariensis (both morphotypes) also enter this assemblage on 

sheltered shores, particularly in western Scotland (e.g. Ilalnabraid Glen, 

Campbelto'rvn, Kintyre; near Neu'ton Stewart, Kirkcudbrightshire). 

Further stuCics may well show that this facies merits the status of a distinct 

association. 

On rocky coasts, dry sheltered overhangs within the Rarnalinetunt 

scopuluris support the Sclerophl:tetum circumscripttte, discussed bclos,. 

Sclerophytetum circumscriptae ass. nov. (Table XV) 

The Sclerophytetum circumscriptae is a very distinctive association charactcristic 

of clry, often shaded, recesses in siliceous maritime rocks u'hich 

arc not subject to direct rainfall. This association, which is largely restricte d 

to the south and wcst coasts of the British Isles, includes many rare 

specics often at the northern edges of their distributional ranges. Thc most 

characteristic species of this community are Caloplaca arnoldii, C. littorea, 

Arth.onia lctba.ta aggr., Catillaria littorella, Dirina stenhammari, Lecanactis 

dill.eniana, L. monsh,osa, Lecanor a tenera, Opegral>ha cesareensis and 

Scl.erophyton ciratmscril>tnm. Lecanora praepostera, Rinodina subglaucescens, 

* Set. foor.notc on prcvious page.

388 P. W. James, D. L. Hazlhszlorth and F. Rose 

Species 

Arthonia lohata aggr. 

Buellia leptoclinoides 

Chiodecton petraeum 

Lecanactis monslrosa. 

Lecanora atra 

L. gansaleoides 

L. praeposlera 

L. tenera 

Lecidea orosthea 

Pertusaria fla.oicans 

Ramalina siliquosa 

Roccella fuciformis 

I?. phycopsis 

S c lerophy tor t cir cuntscriptunt 

Tanrr XV. 

Sclerophytetum circumscriplae ass. nov. 

1.- 

2.2 

+.1 

1.- 

2.1 

+ 

1.7 

J.J 

Stands 

+ )) 

+ J.J 

1.2 

f,1 

1.+ 

2.7 

2.2 

1' Isles of scilly, st Mary: sheltered dry acid rock. incl. 90o, aspect 315., 0.5 x 0.5 

m, 1968, P.W.J. 

2. Channel Islands, Al9":l:I, La Roche peninsula: acid rock, aspect 45., 1 X 2 

m, cover 600/6, April, 1975, p.W.J. ; type yecord. 

Roccella fuc{ormis and, R. phycopsis are present as far north as the islancl of 

skomer, Pembrokeshire, whereas Buehia reptocrinoides, chiodecton myrticola 

and c. pett'aeum are restricted to south-west England and the channel 

Islands. Arthonia atlantica is confined to western Ireland. Further notes 

on the ranges of many of the species in this association within the British 

Isles are included in James (1970). 

It is of interest to note that in south-west Brittany, northern spain and 

Portugal, this association is not confined to crevicls but is also able to 

extend on to exposed rock faces. 

V err uc arietum maur ae DF.. 

soensh. z.tcixtsociol. stiltsh. Haydl.. 2, 51 (rgzs) las ,,verrucaria maura-Ass.,,).verrucaria 

maura-I'ichina confinis-Associatio''DR., Beih. bot. cbl. 49, gl (1932) 

Thc verrucarietum maurae is the association of the littoral (brack) zone on 

all siliceous rocky coasts of Britain. The 15 species which .o-pri." it ur" 

more or less regularly inundated by sea-water on shertered shtres or lie 


within the splash zone on more exposed coasts; only I'ichina pygmaea is 

regularly submergcd by thc tide. Althoush considerable patterns of 

zonatiorr may occur within the Verrucarietum maurae thcse are often 

obscurcd due to variations in shoreline topographv and the density of 

algal cover. This results in the upper and lower elements of this association 

becoming spatially close as on respectively drier exposcd and rvctter, seaweed 

sheltered surfaces in juxtaposition. The Verrucarietu.m maurae is 

dominated by species of Verrucaria thc identification of which still presents 

considcrable problems (Fletcher, 1975a). Verrucaria maura generally 

delimits the upper part of the zone and extends into thc Caloplacetum 

marinae; on some shores this species is associated with V. ampltibia.'fhe 

maximum immersion time for any species in the association is that of 

52o/o of one year recorded for V. striatula andV. mucosa (Fletcher, 1973a); 

these two species constitute the lowest ertension of the zone. Intermediate 

spccies are Arthopyrenia halodTttes, Arthopyrenia sp., Verrucart:.a degelii 

(northern Scotland only), V. ditmatsica, V. erichsenii, V. microspora atrct. 

and V. sandstedei. Arthopyrenia halodytes exhibits a very wide range of 

substrate tolerance, occurring on acid or limestone rocks, on a r,vide range of 

shells of molluscs and on soft chalk (as in south-east England). 

F. Aquatic Cornrnunities 

The lichen flora of siliceous rocks in, or at the margins of, lakes and strearns 

includes a small but distinctive assemblage of species, many of w-hich are 

almost exclusive to the habitat. The horizontal zonation patterns formed 

by particular lichen associations lvithin or below the splash zone are 

comparable with those occurring on coastal rocks (see Santesson, 1939; 

Wirth, 1972). Recently the zonation formcd has proved of value even in 

the determination of river channel capacity (Gregory, 1976). l'he ccology 

and phytosociology of the freshwater communities in the British Isles have 

received little study although the taxonomy of the aquatic species of 

Verrucaria and Polyblastia, two of the most difficult genera represcnted, 

has been critically reviewed by Swinscow (1968, 1971). According to the 

information available there appear to be at lcast lour associations which 

merit consideration. As with the case of the marine and maritime lichen 

communities, no attempt has been made herc' to assign the associations of 

aquatic habitats to alliances. 

Some of the ecological factors which account for the delimitecl distribution 

of aquatic lichens have been discussed by Ried (1960a,b). Probably 

the frequency and sum extent of submersion are t\4-o important controlling 

factors for thc survival of most species; only Verrucat'ia aquatilis, V.

390 P. W. James, D. L. Hauhszoorth and F. Rose 

kernstockii and v. silacea (the siliceous morphotypc of v. elaeomelaena 

according to wirth, 1972) reqtire prolonged submersion. several species, 

for instance, Porina ahlesiana, Verrucaria aethiohola, V. hydrela and 

V. margacea, are markedly tolerant of lovv illumination ancl may, in 

sheltered consistently humid sites, extend to damp rocks some distance 

from the margins of lakes and streams. Alternatively, a f'acies of the 

Opegraphetum horistico-gyyl6erpae, including Enterographa hutchinsi.ae, 

Opegrapha lithyrga, O. zonata and Porina lectissima, as well as Catillaria 

chalybeia and Porina chlorotica, tvvo species rvith an extremely wide 

ecological amplitude, may in similar shaded conditions enter into characteristic 

aquatic associations. 

Both the pH and mineral content of the rvater may exert an important 

influence on the composition of the lichen flora. lt is noteworthy that 

intermittently inundated siliceous rocks at the margins of lakes which are 

fed by streams flowing over basic rocks may develop species-poor facics 

of the Gyalectetum jenensis or the Rhizocarpon petraeum nodum (p. 362), 

including such species as either Gya.lecta jenensis, Lecidella stigmatea, 

Placynthium nigrum, Polyblastia scotinospora, P. theleodes, Lecideo speirea, 

Protobl.astenia rupestris or Rhizocarpon petraeum, respectively. As with 

coastal limestone rocks, there are few lichens characteristic of semiinundated 

limestones or other types of base-rich rock: in Britain only 

verrucaria elaeomelaena and the rare species Placynthium tantaleum. and 

Staurotlrcle succedens seem to belong exclusively to this category. As a rulc, 

semi-inundated limestone supports either moisture-tolerant associations 

of the Aspicilion calcareae or a facies of the conrmunities of dry limestones 

tolerant of some submersion of lvhich rhelidium decipiens can be cited as 

a notable example. 

The communities of lakes and streams seem to be particularly vulnerable 

to contamination by inorganic fertilizers which find their way into 

aquatic ecosystems by run-off and seepage from treated agricultural land. 

The consequent effect is one of more or less intensive hypertrophication 

which encourages the rapid blanket colonization of su,ards of blue-green 

and green algae which rapidly smother the pre-existing lichen communl'ties, 

nearly all of which are dominated by species with crustose thalli and are 

unable to compete under such adverse conditions. Damage to aquatic 

lichen communities in Britain has been accentuated noticeablv in the last 

5 years, particularly in Wales, south-west Scotland and south-west England, 

areas where there has been a rigorously applied policy for the extensive 

reclamation of heathland and moorland for agriculture and forestry; many 

upland streams have become wholly or partly contaminated due to this 

cause. This aspect of freshwater pollution is in need of urgent study. 'l'o a 

lesser degree, the lowering or raising of lake levels and the diversion of 


water from streams and rivers for hydro-electric schemes and the formation 

of reservoirs has had a notable impact on some of the more interesting 

aquatic lichen communities. 

Aspicilietum lacustris Wirth 

Diss. Bot., Lehre 17,223 (1972).-Aspicilietum lacustris Frey,in Frey and Ochsrrer, 

Arternia 2, 67 (1926), ? nom. inoal. as labelled "une fragment". 

In the British Isles, the Aspicilietum lacustris is the u'idespread association 

of the splash zone of lakes and streams subject also to periodic inundation. 

The characteristic species in well lit sites arc Asprlcilia lacustris, Dermatocarpon 

fluxiatile, D. meiophyllum, Rhizocarpon laeaatum, Staurothele fssa 

and Verrucaria aethiobola, often in association with Huilia albocaerulescens, 

H. macrocarpa, Lecidea tumida and Rhizocarpon obscuratum in less frequently 

inundated habitats. With an increase in the degree of shading, a 

nodum also including Bacidia inundata, Catillaria chalybeia, Aspicilia 

laez;ata and Verrucaria praetermlssa is established; this assemblage of 

species is perhaps worthy of recognition at association rank. In very 

shaded and more humid situations the association grades into the Verrucarietum 

siliceae marked by increased frequencies of Verrucaria hydrela 

and V. margacea. The Physcietum caesiae (p. 360) is not uncommon on 

the tops of boulders in streams used as bird perches. 

Several other noda are discernible in the Aspicilietum lantstrr's, for 

cxample, that occurring on very shaded mica schist rocks in small streams 

in western Scotland and Ireland including Microglaena larbalestieri and 

Porina guentheri var. grandis; the more widely distributed Thelidium 

pyrenophoruz is also often present in this nodum. 

Another important nodum mainly confined to Ireland but also represented 

as a species-poor facies in western Scotland is that characterized by 

the presence of Huilia hydrophila, and which may correspond to the 

subunion Haplocarpon hydrophilum of Wirth (1972). Additional characteristic 

species of this nodum are Porina guentheri var. lucens, P. interjungens 

(rare), Porocyphus henmorensis and the ubiquitous Aspicilia lacustris, 

Catillaria chalybeia, Huilia albocaerulescens, H. ftiacrocarpa, and Rhizocarpon 

species. 

'[he Lecidea phaeops-L. taylori community discussed on p. 365 might 

also be placed near here. Most of its characteristic species are markedly 

euoceanic; the previously "endemic" species Lecidea phaeops and L. tayl.6vi 

have recently been collected in the Agores (Faial and Santa Maria) where 

they are dominant in moist woodlands and semi-inundated river valleys 

similar to those in lvhich they occur in Britain.

392 P. W. James, D. L. Hazphsworth and F. Rose 

El>hehetum lanatae F rey 

Mitt. naturf. Ges. Bern 6, 172 (1922) fas,,Ephebe lanata-Ass."l. 

of algae and the bryophytes Bryu ancl 

Rh m are additional important com thc 

ass bryophyte cover is well develop ngia 

tar y, Polychidium muscicola, enter the 

I onas pide turn su ats eolentis F r ey 

Mitt. naturf. Ges- Bern 6, 170 (1922) las "Jonaspis suaz,teolens-Lss."l.-Ionaspidetumodoraewirth, 

Diss.Bot.,LehreL7,223(1972)fas"(tlrey 1922)iom.roo.;,1. 

competition with numerous species of blue-green algae. Thelidium aeneo- 

'uînosa cited by wirth (1972) as a characteristic species in the association on 

the orded from the British Isles (Durhanr). 

Th n higher mountain areas ol Scotlanci, 

par tains where it seldom occurs below an 

altitude of 910 m. At lower altitudes the community grades into the 

Aspicilietum lacustris in u'hich Placynthium pannariellum and. polyblastia 

cruenta, at least above 200 m, may also be present as subsidiary species. 

Verrucarietum siliceae Wirth & Ullrich 

lz Wirth, Diss. Bot., Lehre 17,219 (1972)- 

This association, the verrucariehtm siliceae, comprises communities 

growing on siliccous rocks in streams and lakes where therc is a moderate 


to rapid water flow, sufficient light and lack of mud and silt. Although the 

association is frequently submerged throughout the year it may also bc 

found in shaded strcam beds which dry out for relatively short periods of 

the year. Verrucaria aquatilis, V. hernstochii and V. silicea are characteristic 

of the Verrucarietum siliceae. According to Wirth (1972), V. silicea is the 

siliceous rock morphotype of V. elaeomelaena which occurs in similar 

situations on submerged limestones. \iarious free-living algae of u'hich 

Hildenbrandtia and Lemanea merit particular mention are often present 

as is the moss Fontinalis antipyretica. The rcre Collema fluoiatile is 

faithful to the association in Britain. 

A nodum characterizedby Bacidia inundata, Staurothele fissa, Verrucaria 

latebrosa and V. margacea, not uncommon in western areas of the British 

Isles, is also referred to the Verrucarietum siliceae. This may be identical to 

the V erruc arietum laeo ato- funudatae W irth. 

VII. Terricolous Communities 

In gcneral, terricolous lichens present much greater problems of phytosociological 

delimitation than communities characteristic of other substrates, 

because lichens on soil usually form an intimate and integral part 

of alrcady designated higher plant associations; they do not form the more 

or less exclusive stands seen in the case of most corticolous and saxicolous 

lichen communities. In the case of terricolous communities, lichenologists 

have often adopted classificatory schemes which pay only minor attention 

to the vascular plants involved (e.g. Klement, 1955). While this approach 

can be sympathized with, as those describing higher plant syntaxa have all 

too frequently ignored lichens in their surveys, in our vierv an entirely 

acceptable system for terricolous communities must take a proper account 

of both phanerogam and cryptogam components. 

An outline of the higher plant syntaxa which may be recognized in 

Britain is included in Shirnwell (1971). Those present in Britain as a u'hole 

were summarized by Tansley (1939) although he did not adopt the nomenclatural 

system used by continental workers, and those in Scotland are 

reviewed in some detail in the work edited by Burnett (196+). A survey of 

the plant associations of lowland Britain is currently in progress but results 

from it will not be generally available for some time. 

For simplicity, we have separated the terricolous lichen communities into 

the following four categories, those of pebbles, basic soils, coastal soils 

and acid soils or peat.

39+ P. W. James, D. L. Hawksworth and F. Rose 

A. Pebbles 

Lichens on pebbles may be sporadic within vascular plant-dominated 

communities or form extensive stands in unstable pebble-dominated 

situations. Extremely mobile pebbles are scarcely colonized by lichens, 

perhaps largely due tci abrasion of any incipient thalli. 'Ihree pebble 

communities are particularly distinctive in the British Isles and are 

recognized as associations here as they can occur over large areas with few 

or no flowering plants. 

Huilietum crustulatae (Klem.) P. James et al. 

This association is discussed under saxicolous communities above (p. 370), 

as it can also occur on larger rocks and boulders. 

Lecideetum erraticae ass. nov. (Table XVI) 

This association is particularly well developed on pebbles at Dungeness in 

East Kent, arr area which has a noteworthy facies of the Lecanoretunt 

subfuscae on Sarothamnus and Prunus spinosa (see p. 319) and also Cladon.iadominated 

heathland-like communities on decaying Sarotltamnu.s. f'he 

characteristic species of the Lecideetum erraticae are Buellia aspersax, B. 

aethalea, Lecidea erratica and L. tumida. In a slightly shaded facies, an 

undetermined As1>icilia becomes dominant. Other species occasionally 

found in this association are Catillaria chalybeia, Buellia terruculosa, 

Lecanora dispersa, L. polytropa, Rhizocarpon constrictum, R" obscuratum 

and Verr ucaria nigrescens. This association is optimally developed on 

pebblcs in small declivities in shingle or rvhere there is partial shading 

from adjacent scrub. The species present in this community scem able to 

withstand periodic disturbance; pebbles with thc Aspicilia mentioned 

above frequently have their upper and lower sides colonized by this species. 

Although best developed at Dungeness, this association has also been 

recorded in a more fragmentary state from the Chesil Beach, Dorset; 

Orford Ness, Suffolk; Start Bay, Devon; Pevensey Beach and Pagham, 

Sussex (Rayner, 1976); and Ballantrae shingle beach, Ayrshire. At 

Slapton the association occurs on more stabilized shingle, particularly 

bare patches exposed within the lichen-dominated Cladonietum alcicornis 

(p. 401), and Buellia punctata (saxicolous morphotype) is also a tare 

component there (Hawksworth, 1972a). 

* This is a small sterile sorediate species resembling a slightly brown-grey form of 

Lecidea tumida and, as in that species, has a delicately fimbriate dark prothallus; 

gyrophoric acid is present in the medulla and in the internal part of the soralia. 

Species 

Aspicilia sp. 

Buellia aethalea 

B. aspersa 

B. stellulata 

B. oerruculosa 

Catillaria chalybeia 


L. polytropa 

Lecidea erratica 

L. tumida 

Rhi z o c ar 1t on cons lrictum 

R. obscurututn vzr " 

reduchtm 

Verrucaria nigrescens 

10. Lichen Communities in the Britislt Isles 

Tesrn XVI" 

Lecideetum erraticae ass. nov" 

_)- ) 

2.3 

1.2 

+"0 

.+.0 

.t ..') 

2.3 

7_2 

1"2 

J.J 

+"0 

+.0 

1.2 

2.3 

1"1 

1.3 

J.J 

1.3 

2.2 

1.1 

2.2 

1.3 

1.3 

1.1 

Stands 

+.3 

1,"2 

1.2 

+.0 

1.3 

L,) 

1.2 2.3 

2"3 1.3 

_L1 

+.2 7.2 

- 

)_') .H 

| 

1"3 1.3 

2.2 1.2 

- 

aa 

L.L 

1.3 1.3 

- +-.0 

1. East Kent, Denge Beach, Open Pits (61/073186): pebbles (exposed), level, 

1'0 x 1'0 m, cover 40o,lo, 16 July 1976, P.W.J. 

2. East Kent, Denge Beach, Open Pits (61/077184): pebbles (exposed), incl" 

15', 1'0 x 1'0 m, cover 55|i, 16 July 1976, P.W.J. 

3. East Kent, Denge Beach, Open Pits (61i063173): pebbles (shaded), incl. 

10", 1'0 x 1'0 m, cover 35o/n, 16 July 1976, P.W.J.; type record. 

4. East Kent, Lydd Ranges (61/015182): pebbles, incl.25o, 1'0 x 1'0 m, cover 

45o/",28 June 1968, P.W.J. 

5. Dorset, Isle of Portland, Chesil Beach, Fortuneswell (301675745): pebbles, 

level, 1'0 ). 1'0 m, 16 April 1970, P.\ '.J. 

6. East SulTolk, Orford, Orford Ness (62/448494):pebbles, incl.5', 1'0 x 1'0 m, 

25 June 1964, P.W.J. 

Lecideetum watsoniae ass. nov. (Table XVII) 

Unlike the other two pebble associations recognized here, this association 

is characteristic of basic situations, particularly calcareous (chalk) slopes 

of south-east England. The predominant species of the Lecideetumwatsonii 

on chalk nodules are Lecidea watsonii, Protoblastenia immersa, P. metzleri, 

P. monticola, Sarcogyne regularis, Staurothele hy'menogonia, Thelidiunr 

decipiens, T. incaxatum, Verrucaria hochstetteri, V . muralis, V. mutabilis and 

V. ztiridula. On flints within the same association Aspicilia calcarea, 

A. contorta, Caloplaca citrina, C. holocarpa, Lecanora dispersa, Lecidella 

stigmatea, Protoblastenia rupestris, Verrucaria nigrescens and V. airih,Llq. 

39.s

Species 

Bacidia nruscorum 

B, sabuletorunt 

Caloplaca cilrina 

Collema auriculatum 

C. tenax 

D r r m a I oc a rpon h epat i cu m 

Lecidea watsonii 

Lecitlella stigmatea 

Leptogium schraderi 

L. cf " subtile 

Petraclis clausa 

Physcia adscendens 

Pr o t ob I as t e ni a'immer s a 

P" metzleri 

P" monticola 

P" rupestris 

Sarcogyne regularis 

Staurothele hymenogonia 

Thelidium decipiens 

lf . microccrpum 

Verrucaria hochstetteri 

V. muralis 

V. mutabilis 

V. nigrescens 

V" z.tiridula 

Algae 

Bryophytes 

Phanerogams 

1. 

2. 

3. 

4 

Tarrr XVIL 

Lecideetum watsoniae ass. nov. 

+"0 

)-) 

t,) 

+.0 

7.2 

+.0 

)) 

J) 

-J) 

)') 

tC 

-T"L 

1.3 

)_ ') 

L) 

+.0 

1.2 

ia 

Stands 

J 

Surrey, Dorking, Box Hill (51/184525): exposed chalk/flint pebbles, incl. 10', 

aspect 180", cover 65o/o, 0'5 X 0'5 m, 16 October 1968, P.W.J. 

West Norfolk, Thetford, Thetford Heath (52/845796): recently exposed 

chalk/flintpebbles, incl" 5', aspect 180', cover 7sok,0.5 x 0.5 m, 12 December 

196s, P.W.J. 

\Mest Sussex, Midhurst, Heyshott (411902167): chalk/flint nodules in rabbit 

warren, incl. 35', aspect 225", cover 55o/o, 0'5 x 0'5 m, 6 September 1963, 

P.W.J. 

West Sussex, Midhurst, Heyshott (411902167): chalk/flint nodules in deep 

shade of ,Fagus, rncl.35", aspect 225", cover 7lo/o, 1.0 x 1.0 m, 6 September 

197s, P.W.J. 

5. Hertfordshire, Tring, Coombe Hill (421896106): chalk/flint nodules in shade 

of Corylus, incl. 50", 1.0 X 1.0 m, 3 March 1962, P.W.J. and T. D. V. Swinscow, 

+.0 

+"0 

)) 

t,) 

-T,L 

+.0 

+.0 

+.0 

+.0 

+.0 

-r.L tC 

7.2 

1.3 

-)) 

-) ') 

-t) 

+.0 

1,) 

)-') 

+.0 

+.0 

L,) 

+"0 

],) 

+.0 

-L) 

in 

t') 

1..3 

t) 

+"0 

l', 

)_J 

+.0 

-t-.0 

-l-.0 

+.0 

+.0 

+.0 

L) 

t.E 

+.0 

+.0 

tO t) 

) tL ).L 

t.2 1.3 

+.0 +.0 

-l-"0 +.0 

-t-.2 +.0 

t')t', 

-T.L -r,L 

+.0 

+.2 7.2 

+.0 +.0 

+.0 


can occuf. More locally Petractis clausa and Polyblastia dermatodes on 

chalk, and Ochrolechia parella, Physcia adscendens, P' caesia, P. tenella, 

Xanthoria aureola, X. elegans and X. parietina on flint may entef thc 

community. A fcw primarily soil-loving specie s may also be present, for 

example Bacidia sabuletorum, Collema tenax, Dermatocarpon hepaticum, 

Leptigium lichenoides and L. sinuatum. The chalk nodule flint commrrnities 

foi- u part of those u,idespread on basic soils in areas such as the Breckland 

of East Anglia and the Kent and Sussex Downs, and species found in these 

(see pp. 397-+00) may also occur in them occasionally' 

The Lecideetum watsoniae is optimally developed on dry eroded southfacing 

hillsides in the downland areas of south-east England. It may have a 

somewhat transitory nature to judge from its tendency to occur in areas 

of relativeiy fecent disturbance, as near old rabbit burrows where a fresh 

supply of chalk nodules suitable for colonization has been disinterred. 

A somewhat shaded facies of this association is occasionally encountered, 

most frequently under Fagus, in which Acrocordia monet$is, Thelidiunt 

macrocarpum and Verrucaria muralis on chalk, and V' mutabilis and V' 

ciridula on flints become dominant; the moss Seligeria paucifolia is also 

often represented in such communities. 

B. Basic Soils 

The lichcn communities encountered on soil in the immediate vicinity of 

basic rock outcrops are most appropriately treated as an integral part of 

those occurring on the rocks themselves (pp. 349 364)' For successful 

colonization in such sites the terricolous lichens require open and sumciently 

stable habitats, for example on closely cropped exposed hillsides 

(particularly those with high rabbit populations) and more especially 

pockets oI soil between and on the outcrops themselves. In such habitats 

tlrc vascular plant flora is either reduced in height by gtazing, or by the 

overall thinness, and frequently by the dryness of the soil. Some lichens 

generally treated as terricolous are characteristic of bryophyte-rich 

communities and are themselves predominantly bryophilous (muscicolous) 

rather than strictly terricolous. 

The ubiquitous indicator lichens of basic soils are Bacidia sa,buletorum, 

Cladonia pocillum, Collema tenax (often a primary colonizer of reccntly 

disturbecl soils) and Polyblastia tristicula; a variety of unicellular and filamcntous 

blue-green algae (Cyanophyceae) are also generally present' 

Additional species which are frequently present include Bacidia muscol'Ltm, 

Caloplaca citrina (terricolous morphotypes), Cl,adonia rangiformis, Collema 

crispum, Dermatocarpon hepaticum, Leptogium lichenoides, L" sinuatum, 

Microglaena muscorumt Ptacidiopsis custnanii (in Scotland), Polyblastia


gelatinosa, Squamarina crassa, Toninia coeruleonigricans and T- lobulata. Of 

the rarer or more local species to be found on such soils are Bacidiu 

herbarum, Buellia asterella (syn. B. epigaea auct. angl.), Fulgensia sp., 

Lecidea decipiens, Polyblastia agraria, P. tpheldonii, Squamarina lentigera 

and Verrucaria psammophila. 

In the Breckland of East Anglia, the basic soils support particularly 

interesting assemblages of species, including Buellia asterella, Lecidea 

decipiens, Fulgensia sp. and Squamarina lentigera (Table XVIII). Thesc 

communities may well correspond to the Fulgensietum fulgenlzs Gams 

recognized by many central European authors, but they are in nced of 

further study. Fulgensietumfulgentisisawidespread continental community, 

especially in central and southern France. 

Species 

Tenrn XVIIL 

Lichen-rich community of the Brechland, East Anglia (a/. Fulgensietum 

fulgentis Gams). 

Bacidia muscorum 

Iluellia asterella 

Cladonia foliacea 

C. furcata 

C.1>ocillum 

C. rangifurmis 

Collema tenax 

Cornicularia aculeata 

D erm at o c ar p on hep aticum 

D ip lo s c his t e s s cr up o sus 

var. bryophilus 

Fulgensia afr. fulgens 


Lecidea decipiens 

Peltigera canina 

P. ntfescens 

P r otob I as t enia r u? e s tr i s 

Sarcogyne regularis 

Squamarina lentigera 

Toni n i a rceru I eonigric a ns 

Verrucaria hochstetteri 

V. muralis 

V. nigrescens 

Bryum capillare 

C am1> t o th e c ium lut e s c en s 

Stands 

3+56 

+3 

1 

1 

1 

+ 

1 

2 

+ 

2 

; 

1 

2 

a 

Species 

Ditrichum flexicaule 

Encaly Pt a s tr eP lo c ar P a 

Rhytidium rugosum 

Astragalus danicus 

Batrychiam lunariu. 

Carex arenaria 

C. ericetorum 

Carlina z.tulgaris 

Centaurium erltthraea 

Erigeron acer 

Euphrasia fficinalis 

aggr. 

Festuca o'uina 

Galitmt aerum 

Gentianella anmrella 

Koeleri.a. gracilis 

Leontodon tar axacoides 

Linum catharti.cunt 

Lotus conticulatu.s 

Medica,go lupulina 

Ononis repens 

Ornithopus perpusillus 

Pilosella officinarum 

Pinus syloestris 

Prunella ztulgaris 

Sedum acre 

Senecio jacobaea 

Taraxacum laeztigatum 

T'hytnus spp. 

'lleer.n XY III- c ontinue d 

2 

2 

J 

.t 

2 

2 

7 

l 

+ 

2 

-l- 

5 

+ 

1. West Suffoll

400 P" W. James, D. L. Hazpkszporth and F. Rose 

Future investigations may indicate that specific habitat preferences 

shown by particular species are related to the soil chemistry and cornposition 

as well as to those climatic factors determining which communities 

occur on calcareous rocks. Bacidia sabuletorum and Dermatocarpon 

hepaticum, for example, both have a wide ecological amplitude and can be 

both shade- and moisture-tolerant; hence their frequent occurrence with 

the Gyalectetum jenensis. As in the case r,r'ith dune svstems, the amount of 

calcium carbonate in the soil determines the abundance and species 

diversity of lichen-dominated communities in calcareous sites. Soils with 

100 mg Ca/100 g and a pH usually above 6'2 are the first on which true 

lichen calcicoles are able to survive and where Bacidia sabuletorum, Cladonin 

pocillum, C. rangiformr^s and Collema tenax (often in abundance) occur. 

With increasing pH additional species start to appear but it is only at the 

highest pH levels (to pH 8'2)where lichens such as Fulgensiasp., Lecidea 

decipiens and Squamarina crassa are found. 

There is little evidence to suggest that certain basiphilous lichens can 

grow equally well in sites where magnesium replaces calcium as the 

predominant cation. The lichen flora of the magnesium-rich serpentine 

outcrops in Shetland, as at Baltasound on Unst, for example, have little in 

common lvith that of limestone areas in Sutherland. 

Whilst many of the species mentioned above can be expected to occur 

in most limestone areas of the British Isles, several others appear only with 

increasing altitude. As1>icilia 'uerrucosa, Caloplaca stillicidiorum, Lecidea 

templetonii, Solorina saccata and .S. spongiosa, for example, are predominantly 

montane in England, although they are to be found at sea-level in 

Scotland ',vhere they enter the coastal Dryas octopetala-Carex rupestris 

nodum of McVean and Ratcliffe (1962). A few species are characteristic of 

basic soils between outcrops of limestones and epidiorites in the Highlands 

of Scotland; the communities on rocks of the latter type have already been 

referred to (p. 361). Many of the species in such sites are very rare in the 

British Isles and the communities they form may be fragments of those 

more widely distributed in comparable habitats in western Scandinavia; 

the most important species of these soils in Scotland are Biatorellafossarum, 

Collema ceraniscum, Dermatocarl>on cinereum, Gyalecta geoica, Lopadhm 

fecundum, Microglaena sphinctrinoides, Polyblastia sendtneri, Sagiolechia 

rlrc xoblephar a and Thelopsis melathelia. 

C. Coastal Soils and Dunes 

Very few lichens are restricted to coastal soils in the British Isles and, 

as with most other terrestrial communities, these form an integral but 

often minor part of vascular plant-dominated communities, Most lichens 

10. Lichen. Communities in the British Isles 401 

Cladonia species cornprise the most important element in such communities 

and incluclc i). conistea, C. cerz;icornis (including C. zterticillata), 

C. chlorophaea, C. foliacea, C. nylanderi (rare), C. pityrea and C' pyxidata, 

in adclittn to the ubiquitous C. furcata and C. rangiformis; Peltigera 

species are additional imPort 

On bare soil in expoied 

and Solenopsora 

oultuyiensis occur; thc latter 

sheltered sites or 

on damp rocks in overhangs. Lepraria 

I subcrustose 

leptogium species and Micarea 5 

etimes 

common in shelteted sites but this sha 

poorly 

understood. Loose friable soil of banks may support Moelleropsis nebulosa' 

dunes 

interesting dune lichen vegetation 

which ; this is derived mainly from the 

accum 

be supplemented by run-off and 

erosion of adjaccnt calcareous outcrops (e.g. Broadhaven, Pembrokeshire). 

The most consolidated soils of basic dunes have lichen assemblages

402 P. II'. ./ames, D. L. Hazohsz.oorth and F. Rose 

similar to thosc (p. 397) and thc 

Brecklz'rncl (p. 398 mit their c{evelop_ 

rnent. 'l'he most hi often corrcspon.ls 

to the transitional and the stabilizccl 

grey dunes, as in older dunes there is a leaching of the calcium carbonatc, 

a lowering of the pH and an accumulation of surface humus; all thesc 

factors favouring the establishment of the acid heathland communitl, 

types are cliscussed belor,r, (p. 403). 

N'lost species found on calcareous dunes are also kno,r'n in other lo*'lancl 

calcareous sites; Stluamarina crassa f . pseudocrassa, hou.ever, is noteworthl 

in being exclusively coastal. Bacidia sabuletorum, cladonia rangiformii, 

C. foliacea, C. pocillum, Di1>loschistes scruposus var. bryophilus, Leptogiunr 

lichenoides, L. sinuatum and Peltigera rufescens are indicators of l.ery lor,r 

but perccptible concentrations of calcium carbonate in the dune sancl. 

\vitlr increasing pH and calcium carbonate levels, species such as Dermatocarpon 

hepaticum, Polyblastia gelatinosa, P. tristiutla, P. wheldonii (rarc) 

and l'oninia coeruleonigricans appear. Arthopyrenia subareniseda ar.rd 

Polyblastia agraria are so far confined to this habitat in Britain. In areas 

rvhcre the soil is extremely calcareous, Fulgensia sp., Lecidea decipiens, 

Placynthium nigrum, Squamarina cressa, Toninia aromatica and 1'. lobulata 

may be found. 

D. Acid Soils and Peat 

Nlost acid heathlands in Britain are dominated by a single species, Calluna 

rulgaris, which often forms more or less extensive tiered stands over large 

areas. Gimingham (tn Rurnett, 1964) notes that since dominance by this 

species is established over such a wide area, there is in consequence a 

considerable floristic diversity in the communities dominated by calluna. 

in the Rritish Isles;the tern "Callunetum" thus conveys little ecological 

information unless qualified in some way. calluna may occur in almost 

pure stands or form intcgrated associations with other species indicative of 

particular habitats, for example Arctostaphylos uz:a-ur si (lvetter facies or 

higher altitudes), Empetrum nigrum (high montane but descending to sealcvel 

in Shetland), Erica c,inerea (dry oceanic moorland), E. tetralix (wet 

rnoorland), vaccinium myrtillus (dry lou'land heaths or hcathlancl under 

trees) and V. uliginosutn (high montane heathlanci). The age of the community 

and frequency of burning arc of considerablc importance in 

relation not only to the diversity of the vascular plant flora but also to that 

of the cryptogarns, including lichens. Open communities show a sequence 

of lichcn development after burning; Lecidea gtanulosa, L. uliginosa and 

pometimes Baeomyces rufus arc amongst the first species to appear, but in 

1(). Lichen Communities in tlte British Istes 403 

the following 5-6 years a more species-rich community forms. Eventually 

the Calluna becomes too dense and/or tall, and lichens are grarlually 

excluded from the community, often forming aberrant morphotypes 

difficult to determine before they are finally lost. In the casc of old Cttlluna, 

bushes, tlre larger Cladonia species (".g. C. arbuscula, C. irnpexa) and 

others (".g. C. floerheana) can often be seen to colonize thc central open 

dying parts. The various cffects of man on acid heathlands are discussed 

firrther by Hawkswotth et al. (I97+)- 

'[he Cladonrzz-dominated communities of rotting logs, rotting tree 

stumps and tree bases not uncommonly spread on tc adjacent soil provided 

that this has a very high humus content. These commuuities, which 

cannot be regarded as strictly terricolous or corticolous and are trcated 

under tlre Cladonion coniouaeae here (pp. 313-314), includc those of the 

floor of mature pine woods in the Scottish Highlands u'ith seve ral very 

rare Cladonia species (".g. C. carneola, C. botrytes and C. cenotea). 

1. Lowland Heaths 

Lowland heathland communities in dry sandy situations support a 

ubiquitous assemblage of species, most of rn'hich belong to the genus 

Cladonia (see Fig. 13): C. arbuscula, C. bacillaris (rare), C. cerz'icornis 

(incl. C. zterticillata), C. chlorophaea (all chemotypes) , C. coccifera, C. 

coniocraea, C. crispata var. cetrariiformis, C. Jloerkeana, C. furcata, C. 

glauca, C. gracilis, C. gonecha (rare), C. impexa, C. pityrea, C. polydactyla, 

C. squamosa (including var. allosquamosa), C. subulata, C. tenuis and 

C. uncialis ssp. diaaea. Additional important species include Baeomvces 

roseus, B. rufus, Cornicularia aculeata, C. muricata, Icmatlophila ericetorum 

(rare), Lecidea granulosa, L. oligotropha (rare), L. ukginosa and P)tcttothelia 

papillaria. Srnall siliceous pebbles in lou'land heaths often support 

fragnrents of the Huilietum crustulatae (p. 370). 

A particularly wet facies of the above assemblage, rvhilst retaining 

Cladonia crispata, C. squamosa and C. uncialis ssp. dicraea, may also bc 

partially dominated by C. strepsrZs; the other species indicated above 

then tend to be restricted to the crowns of tussocks or othcr raised areas. 

'fhis is a particular feature of dying tussocks of Carex pa.niuLlata. and 

Molinia coerulea in bogs where lichens are otherwise abscnt. Another 

facies of particular interest is the occurrence of Cetraria islandica on 

lowland heaths of East Yorkshire, Lincolnshire and Norfolk; old rccords 

suggest that this species was formerly common in such areas. 'fhis facics 

is almost ccrtainly allied to the richer but comparable comrnunities occurring 

near sea-level in the Netherlands and west Jutland, Denmark. 

Although most lichens in heaths disappcar rvith the incrcasing tlcnsity

Eo 

:9 

_o 

6q 

: 

ES 

9: 

uE'. 

u*.: 

,d@ 

o 

U lLI 

kl3 

'i €- 

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tv 

! *l: 

oiN 

\ so\ 

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of the vascular plant vegetation (and sometimes bryophyte cover), Cladonta 

&rbuscula, C. impexa, C. tenuis and, to a lesser extent, C- furcata and C. 

sradlis may persist. This tendency is almost cer 

"growth (towards the light) and ability to decay 

ih"y gto*. Furthermore, these species have 

rate amongst the lichens (see Chapter 3) and so are more able to compete 

with the less vigorously growing vascular plants. 

2. Blanket Peat 

Blanket peat bogs, which cover large tracts of countryside in northern and 

western Britain, support lichen communities generally similar to those of 

the more lowland heathlands discussed above but occasionally have 

species which also occur in upland heaths. As peat becomes exposed either 

through drainage, river action, peat-cutting by man or erosion, lichendominated 

stands develop on the lips or "hags" which remain. Of particular 

importance in such sites are Cladonia coccifera, C. bellidi.flora, C. ceroicornis, 

C. gonecha, C. polydactyla, C. squamosa, Icmadophila ericetontm and 

Pycnothelia papillaria, but several other noteworthy species occur in this 

type of habitat, for example Coriscium airide (with Thelocarpon epibolum), 

Cladonia fragilissima (rare oceanic) and. Lecidea glaucolepidea. 

3. Upland Heaths 

Detailed surveys of the floristics of upland heaths in the Scottish Highlands 

have been prepared by McVean and Ratcliffe (1962) and McVean (r,lz 

Burnett, 1964). These authors presented data on the lichens in many of 

the communities they recognized and in some cases used them in the 

delimitation of the syntaxa themselves. The lichen-rich heaths as interpreted 

by McVean and Ratcliffe fall into two main categorics, the dwarf 

shrub heaths and the moss heaths. The former include noda such as the 

Ar ctoeto- C allunetum of the northern highlands, lhe C ladineto-C allunetum 

vvhich occurs at high altitudes and includes species such as Alectoria sarmentosa 

ssp. z,exillifera and Cetraria nioalis, and the Cladonia-rich 

Cladineto-Vaccinehtm which is central and eastern as well as montane in 

Scotland. Most facies of the moss heaths are dominatedby Rhacomitrium 

lanuginosum, but a few associated with patches of late snow-lic lack this 

species and are dominated by the diverse Gymnomitrium concinnatum-Sulix 

herbacea associations. The lichen flora of the mountain tops in the Scottish 

Highlands is still relatively poorly understood both from the taxonomic and 

ecological standpoint; indeed many upland areas have not been studied 

by lichenologists at all in recent decades. For these reasons we have not 

40-5

406 P. W. James, D. L. Hazohszoorth and F. Rose 

attempted here to relate our observations to the communities distinguishecl 

by McVean and Ratcliffe (1962). 

Some of the rarcst and most interesting species in IJritain occur in 

upland heaths, such as those on the summit peaks of the Cairngorm 

mountains. The lichen-rich communities in montane situations in Scotlancl 

appear in general, however, to be species-poor variants or relics of morc 

widespread Scandinavian (particularly Norwegian) communities. The most 

important lichen species in these communities in Britain arc mainll, 

concentrated in sites which are relatively dry and dominatecl by Sair-r 

herbacea; vvet sites become bryophvte dominated. 'l'he lou'-grouing, 

prostrate, r.r'oody stems of S. herbacea which shed thcir leaves in l.inter 

provide adequate anchorage for many macrolichens and soil-stabilizing 

species. The lichen flora developed might perhaps be considered as an 

oligotrophic countcrpart of the lichen assemblage associated u'itli the 

base-rich mica schist soils of the Ben Lawers range (see p. 362) and 

includes: Baeomyces roseus, B. rufus, Catillaria contristans, Cladoni.a 

luteoalba, Lecanora epibryon, Lecidea assimilata, L. caesioatra, L. granulosa, 

L. stenotera, Micarea melaena, M. h.trfosa, Ochrolechia androgyna, O. 

,frigida, O. geminipara, O. tartarea, Pertusaria oculata, Porina mammillosa, 

Tltamnolia z:ermicularis (var. subuliformis), Toninia haz:aasii, T. tristis, 

T. squalescenr and ?. squalida. 

In bare areas adjacent to Salix herbacea (sce Iiig. 14), colonies of 

Cetraria delisei, Cornicularia aculeata, C. muricata, StereocatLlon saxatile, 

and, very rarely, C. diaergens are developed. These species, together u'ith 

Alectoria ochroleuca.* (very rare), A. nigricans, A. sarm.entrs.rrz ssp. z;exillifera, 

Cetraria ericetorum (rare), C. islandica, C. nixalis, Pertusaria dactylina, 

Thamnolia ztermicularis and Cladonrz species fespecially C. bellidifara, 

C. coccifera, C. de-formes (rare), C. gonecha, C. impexa, C. graci.lis, C. 

tenuis and C. uncialis) occur in Rhacomitrium lanuginosarn-dominatcd 

areas and all have the ability of either growing on or ovcr this moss, or of 

vertical grorn'th which enables them to compete successfully u'ith it. The 

very rare Nephroma arcticum and Platismatia norz:egica occur in the Poly,goneto-Rhacomitretum 

lanuginosi and Arctoeto-Callunetum respectively of 

McVean and Ratcliffe (1962). 

While emphasis has been placed on the lichen-rich communities of 

mountain tops in the above, it is important to note that many of the same 

species also form an integral part of the subalpine Calluna Vaccinium 

uliginosum-Empetrum nigrum communities which often lie on more 

inclined adjacent mountain slopes; in such situations the abundance of 

* It should be noted that, as pointed out by Hawksworth (1972b), the numerous 

rcferences to this spccics b-v NllcVean and Ratcliffc (1962) refer to Alectoria 

s ar me nt o sa ssp. t ex i.llifer a. 

10. Lithen Cotnmunities in the Rritish Isles +07 

Frc. 14. Upland hcath comtnunitl'. 5o".1". prcsent inclr-rde: (-etraria niz:alis, 

Cladonia bellidi.flora, C. tot:cifertr, C. cris\ata, C. inryc'to, ('. tuttiuli.s ssp dicraea, 

Eufl>ellunt nigrunt, ()throlcclia frigida (predominant) and l'arcittittttt t'itis-idaea 

(Cairngorm rnountains, Cairn Gorm summit plateau, 197+, P. W. Jarnes). 

Alectoria sarmentosa ssp. ztexiiiifera, Cetraria n.ioalis, C. islandica and 

species of Cladonia subgen. Cladina is particularly striking. 

Although thc optimal development of upland heaths in the British Isles 

occurs in the Scottish Highlands, comparabie but spccics-poor communities 

are to be found on the highest mountains in Englanc{ (c.g. Chcviot I'Iiils, 

Lake District) and Wales (e.g. Snowdonia). 

VIII. Surnrnary 

Follou'ing a brief rcvierv of previous studies on lichen cornmunities in the 

Ilritish Isles, the value of the phytosociological approach to these is 

discussecl as are the difficulties inhercnt in such mcthocls. Some of the 

nornenclatural problems arising in the naming of plant communities are 

discussecl and proposals are made for changcs in ordcr both to overcome 

thcrc ancl to bring the nomenclatural practice for syntaxa more in line rtith 

that for plant taxa (idiotaxa). The major part of the chapter is concerned 

r,r'ith a survey of thc principal lichen communitics in thc British Isles. In

408 P. W. James, D. L. Hazt:ksworth and tr'. Rose 

the absence of a great deal more field work, an entirely definitive classification 

cannot be presented, but it is hoped that this preliminary conspectus 

will serve both as a framework for the future naming of lichen 

communities in Britain and as a stimulus to further work in this field. 

Topics requiring more detailcd investigation are emphasized throughout. 

The epiphytic communities are grouped in eleven alliances, those on 

limestone in two, and those on siliceous rocks in eight. some associations, 

however, have not been referred to any alliances, as in the case of those 

which occur on moderately basic rock and in marine, maritime and 

aquatic habitats. Terricolous communities remain mostly unnamed here 

as they appear to be most appropriately described together with the 

vascular plants with which they occur. Two new alliance names are 

introdtrced (Parmelion laeoigatae, P. perlatae) and three neu,combinations 

made at this rank in accordance with changes in the generic names of the 

species on which their names were based. Eleven new associations are also 

described and five new combinations made at that rank. A key to the 

epiphytic alliances is included as are tables of relevd data for most of the 

main associations treated and synopses of the synonymy of the community 

names employed. 

Note on the Relev6 Tables 

The relevd data are expressed in tl-re tables of this chapter by one of two 

methods depending on the recorder: either by the f+10 Domin scalc 

or the Braun-Blanquet f-+5 scale, in ivhich case a sociability score on 

the 0>5 scale is appended after a full-stop. Detailed informat'ion on the 

meaning of these units is included in shimwell (197r). Data on inclinations, 

aspects, altitude etc. are included wherever available. Angles of inclination 

are measured from the horizontal, the recorder facing the substrate (i.e. 

90o : vertical, 100' : inclined away from the recorder at 10.). 

*Acknowledgements 

we are very grateful to Mr B. J. coppins for his constructive comments 

on our manuscript, to Drs o. wilmanns and v. wirth for the loan of 

copies of several important early publications on lichen phytosociology, 

and to Mr P. w. Lambley for making available to us his unpublished 

relevds from the Breckland. 

10. Lichen Comntunities in the British, Isles +09 

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