zyxwvutsrqp Nord. J. Bot. - Section of tropical taxonomy zyxwvutsr zyxw zyxwvut The genus Colpodium (Gramineae) in Africa 0. Hedberg and I. Hedberg zyxwvu zyxw Hedberg, 0. & Hedberg, I, 1994. The genus Colpodium (Gramineae) in Africa. - Nord. J. Bot. 14: 601-607. Copenhagen. ISSN 0107-055X. Recent collections of the genus Colpodium from Ethiopia and South Africa made a renewed revision of the African material of this genus desirable. Apart from the two earlier recognized African species (C. chionogeiton and C. hedbergii) a third one is described (C. drakensbergense), restricted to the Drakensberg area of eastern Lesotho and amply distinct both in morphology and chromosome number. The phytogeographical position of Colpodium is briefly discussed. 0. Hedberg and I. Hedberg. Department of Systemutic Botany, Uppsala University, Villuvagen 6, S-752 36 Uppsala, Sweden. new revision of the African species, a need which was accentuated by the work on the Flora of Ethiopia. Introduction When Tzvelev (1964) published his revision of the genus Colpodium Nevski, I9 species were known to him; later 6 more have been described (Bor 1970; Malyschev 1971). He also made a subdivision of Colpodium into five subgenera (Hyulopoa Tzvel., Puracolpodium Tzvel., Nevskia Tzvel., Catubrosella Tzvel., and Colpodium s. str.). In a later publication three of these were segregated as independent genera (Tzvelev & Bolchovskieh 1965). Both Colpodium s. str. and Puracolpodium were later revised by Alexeev (1980, 1981). Clayton & Renvoize ( 1986) reestablished the genus Colpodium in its earlier wide sense, and their circumscription of the genus is followed here. The discovery of the somatic chromosome number 8 in grass collections from Mts Kenya and Kilimanjaro referred to Agrostis chionogeiton Pilger, and in a collection of a closely related taxon from Mt Elgon (0.Hedberg 1952) caused Melderis (1956) to create the genus Keniochlou to harbour these taxa. Later Tzvelev (in Tzvelev & Bolchovskieh 1965) united Keniochlou with Colpodium Nevski s.str. In his account for Flora of Tropical East Africa Clayton (1970) accepted this transfer and provided a detailed revised account. The discovery of this genus both in Ethiopia (0. Hedberg, unpublished) and South Africa (van Zinderen Bakker & Werger 1974) prompted a Accepted 16-6-1994 0 Material and methods The present revision is mainly based on herbarium material obtained on loan from EA, K, PRE, S and UPS (abbreviations according to Holmgren et al. 1990), but it was also possible to study specimens in their natural habitats both in Ethiopia and in Lesotho. The figures used for the diagrams represent means of measurements of five spikelets and (as far as possible) five panicles. Chromosome counts were partly made in sections of root tips (cp. 0. Hedberg 1952), partly in squash preparations (cp. I. Hedberg 1970: 154). Results and discussion Morphology The Tropical African taxa treated here are - like those Eurasian species with which they were united by Tzvelev & Bolchovskieh (1965: 1320) in the subgenus Colpodium - characterized by one-flowered spikelets with soft tex- zyxwvutsr NORDIC JOURNAL OF BOTANY NORD. J . BOT. 14: 601407 39 Nord. 1. Bot. 14 ( 6 ) (1994) 60 1 I zyxwvutsrqponmlkjihgfedcbaZY zyxwvutsrqponm zyxwvuts zyxwvuts 1 I 2 I 3 I I 4 5 Fig. I . Scatter diagram illustrating correlated variation in lemma length in mm (vertical axis) and palea length (horizontal axis) in a representative material of Colpodium chionogeiton (dots) and C. hedbergii (circles). Collections measured were of the former: Bie 35, 117, 135 and 141, Hedberg 1253, 1902 and 3759, King 6; of the latter: Hedberg 5361, 5492, 5618 and 5654, and Phillips 28; all at UPS. J- 0 0 0 4- 0 0 3- The somatic chromosome number 8 reported by 0. Hedberg (1952) for Colpodium (Keniochloa) chionogeiton and C. hpdbergii was confirmed in four additional collections of the latter species from Ethiopia (Tab. 1 and Fig. 4 A). Material from the Drakensberg in Lesotho, on the other hand, deviated not only in basic number but also in ploidy, with the presumably tetraploid somatic number 20 (Fig. 4 B). It is interesting to note that the Eurasian species C. versicolor (Stev.) Woron., considered by Tzvelev & Bolchovskieh (1965) most closely related to the African species, approaches them in its basic chromosome number, which according to Sokolovskaja & Probatrova (1977), Gviniadnidze & Avaznelii (1982) and Davliadnidze (1985) is 2 - half of that found in the African species, and the lowest number found in angiosperms. From the cytological and morphological data summarized above it is evident the the Drakensberg material represents a distinctive species, characterized by its deviating chromosome number as well as by it decumbent habit and its short and unequal glumes (Fig. 3). It is described below as Colpodium drakensbergense. zyxwvutsrqpo 2- 1- Chromosome numbers zy zyxw zyxwvutsr 6- 5- ture, awnless lemma with nerveless tip, and frequent occurrence of clavate-tipped hairs on palea and lemma. The main morphological characters used for specific distinction in the tropical African material by Melderis (1956) and Clayton (1970) were panicle shape (contracted in C. chionogeiton, open in C. hedbergii) and spikelet length (longer than 3.5 mm in C. chionogeiton, shorter than 3.5 mm in C. hedbergii). In the material earlier known there seemed to be a clear-cut distinction between these species both in panicle shape and in spikelet length, but some recent collections deviated so much that it was tempting to question interspecific distinction. Further detailed studies disclosed, however that the two taxa also differ in floret morphology: in C. chionogeiton the lemma is distinctly longer than the palea, whereas in C. hedbergii they are of comparable length (Fig. I). The combined variation pattern summarized in Fig. 2 therefore supports interspecific distinction between them. The South African material is distinguished from that of Tropical Africa by its decumbent and rooting stem and by its distinctly unequal glumes, shorter than palea and lemma (Fig. 3). Fig. 2. Pictorialized scatter diagram illustrating correlated variation in some characters studied in tropical African material of Colpodium: spikelet length in mm (vertical axis) and ratio of panicle length to panicle width (horizontal axis). An open circle corresponds to a specimen where palea and lemma are equilong (C. hedbergii). a filled circle to a specimen with palea and lemma of unequal length (C.chionogeiton). A tail means that at least some panicle branches are reflexed. 602 Ecology All three African Colpodium species are definitely depending on a high water level, either along streams or in small shallow pools, and are restricted in East Africa to the afroalpine belt, in Lesotho to the austroafroalpine belt. Nod. J. Bot. 14 (6) (1994) zyxwvuts zyxwvutsrq zyxwvutsrqp zyxwvutsrqponm zyxwvutsr zyxwvu zy 4 I zyxwvutsrqponm Fig. 3. Colpodium drakensbergense drawn from Hedberg 82009 (UPS). - A. habit x 1.3. - B. Ligule x7. - C. Spikelet x 15. D. Flower x30. - E. Lodicules x30. - F. Palea x 15. - G. Lemma x 15. - H. Upper glurne x 15. - I. Lower glume x 15. 39' Nod. J. Bot. 14 (6) (1994) 603 zyxwvutsrqp zyxwvu zyxwvu zyxwvutsrqpo Tab. I . Chromosome numbers in African Colpodium (cp. 1. Hedberg & 0. Hedberg, 1977) Taxon 2n C. chionogeiron 8 C. hedhergii 8 C. drukensbergense 20 Locality Voucher Mt Kenya, 4250 m Hedberg 1902 Hedberg 1759 Hedberg 1253 Bie 35 Hedberg 908 Hedberg 5361 Hedberg 5492 Hedberg 5645 Hedberg 56 I8 Hedberg 82088 Mt Kenya, 4450 m Kilimanjaro, 4830 m Kilimanjaro, 3800 in Mt Elgon, 3600 m Simen Mts, 3600 m Simen Mts, 3700 m Bale Mts, 4100 m Bale Mts, 4150 m Drakensberg 2900 m Phytogeography The genus Colpodium s. lat. occurs from Turkey and Caucasus to Nepal and eastern Siberia, extending southwards through the Ethiopian and East African high mountains to the Drakensberg in Lesotho (Fig. 5). Since the diversity of the genus is much larger in Asia than in Africa - from Iran alone 12 species have been reported (Bor 1970) - the actual distribution pattern must obviously have resulted through dispersal from the north. The southward migration has evidently been accompanied by a rise in basic chromosome number, to 4 in East Africa and 5 in the Drakensberg. The karyotypes are not very helpful in tracing this evolution, however, each of the three African species has two SAT chromosomes and the other chromosomes are more or less metacentric with little size variation (Fig. 4). Additional support for Iran and surrounding countries as centre of diversity (if not origin) of this group is the occurrence there of the genus Zingeriu P. Smirn., which comprises annual species only and was believed by Tzvelev & Bolchovskieh (1965) to be closely related to and perhaps derived from Colpodium subgenus Colpodium. Bjorkman ( 1 956) also found great similarities in lemma epidermis and other spikelet characters between Zingeria and “Keniochloa” (cp. Bjorkman 1960). It is particularly interesting in this connection that Zingeria also resembles Colpodium subgenus Colpodium in the occurrence of the extremely low basic chromosome number 2 (Sokolovskaja & Probatova 1979; Clayton & Renvoize 1986). In the afroalpine flora Colpodium belongs to the Himalayan flora element (0.Hedberg 1965, 1986), whereas in the austro-afroalpine flora of the Drakensberg it is brought to the “northern temperate group” (van Zinderen Bakker & Werger 1974: 47). Taxonomy Colpodium Trinius zy (1820: 1 19); Tzvelev 1964: 5-19; Clayton 1970: 49; Alexeev 1980: 4; Clayton & Renvoize 1986: 103. - Type species: Cul- podium versicolor (Stev.) Schmalh. Keniochlou Melderis 1956: 538; 0. Hedberg 1957: 53. Type: K. chionogeiron (Pilg.) Meld. Cutuhrosellu (Tzvel.)Tzvelev 1965: 1320. -Type: C. hurnilis (Bieb.) Tzvel. Hvu/(ipoa (Tzvel.) Tzvelev loc. cit. - Type: H. pontica (Bal.) Tzvel. Paracolpodium (Tzvel.) Tzvelev loc. cit.; Alexeev 1981: 86. - Type: P ulruirum (Trin.) Tzvel. zyxwvutsr zyxwvutsr Fig. 4. Metaphase plates from root tip squashes of Colpodium, x 1200. - A: C. hedbergii; - B: C. drukensbergetue. - A from Hedberg 5492 (Ethiopia, Simen), B from Hedberg 82088 (Lesotho, Sani Pass). 604 Small perennials. Leaves flat or folded, with boat-shaped tip. Panicle spiciform or spreading. Spikelets in African species 1-flowered, in some Asian species up to 4-flowered, awnless, with persistent firmly membranous glumes with hyaline margins and obtuse or subacute tip. Nord J. Bot. 14 ( 6 ) (1994) zyxwvutsrqpo zyxwvutsrq Fig. 5. Known distribution of the genus Colpodium in Africa. Filled circles C. chionogeiron, open circles - C. hedbergii, triangle C. drakensbergense. zyxwvu zyxwv Key to species in Africa 1. ~l~~~~ distinctly unequal, than lemma and palea; stems decumbent, rooting at the nodes . . . . . . ....................... 3. C.drakensbergense - Glumes equal, overtopping lemma and palea; stems erect and tufted . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. %)jkelets at least 3.7 mm long; panicle usuah' contracted with all branches erect and lengtwwidth ratio Nord. J. Bot. 14 ( 6 )(1994) above 3; palea distinctly shorter than lemma. . . . . . . .......................... 1. C. chionogeiton Spikelets at most 3.5 mm long; fully developed panicle open with at least some branches reflexed and lengthlwidth ratio below 3; palea and lemma equal or subequal ...................... 2. C. hedbergii zyxwvuts zyxwvut zyxwv Lemma thinly membranous, 3-5-nerved, glabrous or pubescent with appressed clavate-tipped hairs. The genus comprises about 20 species, occurring from Turkey and Caucasus to Nepal and eastern Siberia, and furthermore on African high mountains from Ethiopia to Lesotho. Restricted to high mountain areas (Fig. 5). - 1. C. chionogeiton (Pilg.) Tzvel. Tzvelev in Tzvelev & Bolchovskieh 1965: 1319; Clayton 1970: 5 I , Fig. 18; Alexeev 1980: 8, Fig. 2: 1-6. - Agrostis chionogeiton Pilger 1926: 5 10. - Keniochloa chionogeiton (Pilg.) Melderis 1956: 540, Fig. I : 2; 0. Hedberg 1957: 53. Type: Kenya, Mt Kenya, w alpine region, Fries 1400a (S holotype, K, UPS isotypes). Agrostis oreades Peter 1930: 87. - Keniochloa chionogeiton var. oreades (Peter) Melderis 1956: 540, Fig. 1: 3; 0. Hedberg, 1957: 53. - Colpodium oreades (Peter) Alexeev 1980: 8, Fig. 2: 605 7-1 I . -Type: Tanganyika, Kilimanjaro, Peter’s Hut to Mawenzi saddle, Peter 41928 (B holotype, not seen). appressed pubescence of clavate-tipped hairs. Palea equilong with lemma. Tufted perennial with erect or ascending culms 4-40 cm high. Leaf blades flat or folded, up to 17 cm long and 4 mm wide. Ligule 2-6(-14) mm long. Panicle usually contracted, often spike-like, 1.5-1 2 cm long, its basal part often concealed in the slightly inflated sheath of the uppermost leaf. Spikelets 3.7-6.5 mm long, narrowly elliptic, light green to purple. Glumes equal, longer than lemma. Lemma 3.3-4.9 mm long, 3-nerved, glabrous or with appressed clavate hairs. Palea 2.9-4.2 mm long, distinctly shorter than lemma. Chromosome number. 2n = 8 (cf. Tab. I). Fig. 4A. Distribution. Ethiopia, Gondar, Simen, Geech, Hedberg & Getachew 5492,5361 (EA, ETH, FI, K, PR, ROML, S, SRGH, UPS). Bale, Bale Mts National Park: on the crest S of Garba Goracha camp site, Hedberg 5645 (EA, ETH, K, PR, UPS); Saneti Plateau, Hedberg 5618 (EA, ETH, FI, K, PR, ROML, S, SR, GH, UPS) and 9067 (UPS), S. M. Phillips 28 (ETH, K, UPS). Kenya, Mt Elgon, at Maji ya Moto, Hedberg 908 (EA, K, S, UPS). Mt Kenya, Teleki valley, Aichhorn 7 (EA); Kaziba valley, Hanid 157 (EA). zyxwvutsrqp zyxwvuts The population on Kilimanjaro was described by Peter as a separate species (Agrostis oreades), treated by Melderis as a variety of Keniochloa chionogeiton, and by Alexeev as an independent species, Colpodium oreades. It was claimed by Alexeev to differ from C. chionogeitiun by having the lemma more or less hairy in the lower part, glumes 1-3-veined, and anthers 1.2-1.3 mm long (as against glabrous lemma, glumes 3-nerved and anthers 0.6-0.8 mm in C. chionogeiton on Mt Kenya). Investigation of a larger material demonstrated that the pubescence of the lemma is too variable to be of taxonomic use, however. In all collections examined the lower glume is practically always I-nerved, the upper one 3-nerved. The only difference remaining is that the anthers studied measured 0.9- l .2 mm in Mt Kenya material and l .O-2. l mm in Kilimanjaro material, a difference which does not merit taxonomic recognition. Habitat. In shallow water along streamsides or in small pools, 3 6 0 W l S O m. 3. Colpodium drakensbergense 0. & I. Hedberg n. SP. C. hedbergii affine sed glumis distincte inaequalibus palea brevioribus, caulibusque repentibus nodis radicantibus praecipue differt. - Orig. coll. Lesotho, Qacha’s Nek Distr., Sani Pass lodge, 2860 m, in small dried-out pools, Hedberg 82088 (UPS holotype, EA, ETH, K, PRE, ROML isotypes). zyxwvutsrq zyxwvuts zyxwvutsr Chromosome number. 2n = 8 (cf. Tab. 1). Distribution. Kenya, Mt Kenya, alpine region, Fries 1400a (S); Hedberg 1759, 1902 (EA, K, S, UPS). Tanzania, Kilimanjaro, Mawenzi, Hedberg 1253 (EA, K, S, UPS); King 6 (EA, UPS); saddle between Kibo and Mawenzi, Goyns 18 (PRE); W slope in upper Umbwe Valley, Bie 35, 117, 135 and 141 (all UPS). Carabrusa aguarica auct. non (L.) Beauv.: Andersson 1969: 73. Colpodium hedbergii auct. non (Meld.) Tzvel.: van Zinderen Bakker & Werger 1974: 41, 47. Colpodiurn sp. nov. in Killick 1978: 551. Perennial with decumbent-ascending stems, branching and rooting at the nodes. Leaf blades up to 1 1 cm long and 5 mm wide, usually flat. Ligule 2 4 mm long. Panicle ovate, open, 3-10 cm long, its basal part often remaining in the uppermost sheath. Spikelets 2.3-3.5 mm long, narrowly elliptic, light green with purplish tinge. Glumes distinctly unequal and much shorter than lemma, obtuse. Lemma and palea equilong, 2.3-3.5 mm, both denticulately obtuse and glabrous. Habitat. On moist ground along small brooks, 38005000 m. Chromosome number. 2n = 20 (cf. Tab. I). Fig. 4B. 2. C. hedbergii (Meld.) Tzvel. Tzvelev in Tzvelev & Bolchovskieh 1965: 1319; Clayton 1970: 51; Alexeev 1980: 9, Fig. 1: 14-19. - Keniochloa hedbergii Melderis 1956: 542, Figs. I : upper row, and 2; 0. Hedberg 1957: 54. - Type: Kenya, Elgon, in the crater, Hedberg 908 (UPS holotype, EA, K, S isotypes). Collecrions orher rhun fype: Qacha’s Nek Distr., Sani Pass, near the lodge, in small rivulet, 3.11.1982, 0. Hedberg 82146 (PR, ROML, UPS). Lesotho, Butha Buthe Distr. ,along the road from Oxbow Lodge to the diamond mine, at a pond, 27.1.1982. 0. Hedberg 82009 (EA, ETH, K, PRE, ROML, S, UPS). Natal, Underberg, in seepage area on summit of Drakensberg, 9000’. 25.1.1966, D. J. B. Killick & J. Vahrmeyer 3730 (PRE). Basutoland, Buthe Buthe, Pone Valley, Mothae Mts., in pools 9700’, 8.1.1958, Liitjeharms (PRE). Lesotho, Drakensberg, Werger I614 (K). Tufted perennial with erect culms 7-40 cm high. Leaf blades up to 11 cm long and 4 mm wide. Ligule 2-8 mm long. Panicle ovate, 4-20 cm long, with spreading branches, some of which are normally reflexed. In young specimens the panicle may still appear contracted, as in Aichhorn 7 (EA). Spikelets 2.4-3.4 mm long, narrowly elliptic, light green or purplish. Glumes equal, longer than lemma. Lemma 2.3-3 mm long, 3-nerved, with 606 Acknowledgements - Herbarium material was obtained on loan from - or studied at EA, K, PRE, S and UPS. For the arrangement of loans we are indebted to the Herbarium at Uppsala university, and for care of living material to the Botanic Garden of Uppsala University. Living material and additional herbarium specimens were kindly sent by Mr S. Bie, Dr A. Jacot Guillarmod and Dr D. J. B. Killjck. Dr Killick also organized an excellent opportunity for us to see and collect material in the - N o d . J. Boi. 14 ( 6 ) (1994) zyxwvuts zyxwvutsrqp zyxwvuts Drakensberg. We are also indebted to Ms Inger Sorensen for drawing Fig. 3 and to Ms Eva Persson for preparing the other illustrations and assisting in various other ways. Assistance on cytological preparation was given by Mrs W. Olsson. The Latin diagnosis was checked by Prof. L. Holm. Valuable comments on the manuscript were given by Dr D. J. B. Killick, Pretoria, Mrs S. Phillips, Kew, and an anonymous reviewer. References Alexeev, E. 1980. Genus Colpodium Trin. s. str. - Nov. Sist. Vysh. Rast. 17: 4-10. (In Russian). - 1981. Genus faracolpodium (Tzvel.) Tzvel. (Poaceae). Nov. Sist. Vysh. Rast. 18: 86-95. (In Russian). Anderson, J. G. 1969. A new generic record for South Africa. Bothalia 10: 73-74. Bjorkman, S. 0. 1956. Zingeriu biebersteiniana (Claw) P. Smirn. - one more grass species with the chromosome number 2n=8. - Svensk Bot. Tidskr. 50: 513-515. - 1960. Studies in Agrostis and related genera. - Symb. Bot. Upsal. 17(1): 1-12. PI. 1 4 . Bor, N. L. 1970. Gramineae. - In: Rechinger, K. H. (ed.), Flora Iranica, Vol. 70. Graz. Clayton, W. D. 1970. Gramineae (Part I ) . - In: Milne-Redhead, E. & Polhill, R.M. (eds), Flora of Tropical East Africa. London. - & Renvoize, S. A. 1986. Genera Graminum. Grasses of the World. - Kew Bull. Add. Ser. 13. Davlianidze, M. 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Zum. SSSR 62: 241-245. (In Russian). Trinius, C. B. 1820. Fundamenta Agrostographiae. - Wien. Tzvelev, N. 1964. De Genere Colpodium Trin. - Nov. Sist. Vysh. Rast. ( I ) 1964: 5-19. (In Russian). - & Bolchovskieh, V. 1965. On the genus Zingeria P. Smirn. and related genera in the family Gramineae - a karyosystematic study. - Bot. Zurn. SSSR 50: 1317-1320. (In Russian). van Zinderen Baker, E.M. & Werger, M.J.A. 1974. Environment, vegetation and phytogeography of the high altitude bogs of Lesotho. - Vegetatio 24: 37-49. zyxwvutsrq zyxwvut zyxwvutsrqpon Nord. J . Bol. 14 (6)(1994) 607