zyxwvutsrq Berlin. August 1992 Feddes Repertorium 103 (1992) 5-6, 327-337 zyx zyxwvuts University of Reading, Department of Botany, School of Plant Sciences, Reading, Great Britain J . D. OLOWOKUDEJO Morphological variation of fruits and infrutescences in Biscirtellcl L. (Cruciferae) With one Figure, one Table and 3 Plates Su m ma ry Z us a m m e n fa ss un g The variation of fruits and infrutcscences in 51 taxa of the genus Biscutellu is reported. The basic structure of the fruit is similar in all species - a stalked strongly compressed indehiscent didymous silicula which breaks from the axis into two one-seeded loculi at mnturity. The peculiar and distinctive nature of the fruit constitutes the most important diagnostic feature for separating the genus from other genera. There is considerable variation in fruit size both within and between some species, e.g. the smallest fruits are found i n B. microcurpu where they hardly exceed 2.5 m m x 5.0 mni while in B. rnegacarpucu they could be as big ;IS 11.0 mrn long and 18.5 mm wide. Prominent among species with significant intra-specific variation are B. lirsiranicu, B. setpercirens, B. glaciulis and B. crrlentina. The apex of the fruit is notched to varying extents except in B. uiiricirluttr where the margins run continuously with the style and the apex i s therefore not notched. Style is persistent and contributes to the distinctive appearance of the fruit and the recognition o f some species. Other variable characters include the pedicel. margin. valve shape and pubescence. The infrutescence varies from a simple raceme t o a much-branched panicle. The flexuous branches of some taxa constitute an important feature for their preliminary identification. Some of these characters are of value in clarifying the taxonomic relationships among some component taxa. Von 51 Taxa der Gattung Bisciitellu wird iiber die Variation der Fruchte und BlutenstSnde berichtet. Die Basisstruktur der Frucht ist bei alien Arten ihnlich: ein gestieltes, engzusammengeprentes unaufgeplatztes zweiteiliges Schotchen, das bei der Reife an der Achse in zwei einsamige Loculi aufbricht. Die eigenturnliche. abweichende Ausbildung der Frucht bildet das wiehtigste diagnostische Merkmal. das dic Gattung von den anderen Gattungen der Cruciferae trennt. In der FruchtgroBe selbst herrscht eine beachtliche Spiinnweite sowohl innerhalb der Arten selbst als auch zwischen den rinzelnen Arten. So wurde die kleinste Frucht mit nur 2.5 x 5.0 mm bei B. microcarpi gefunden, die griinte Frucht mit 11.0 x 18.5 m m lieferte B. macrocarpu. Die bedeutendsten unter den Arten mit kennzeichnender intraspezifischer Variation sind B. hisiranica, B. senipercirens, B. yluciulis und B. calmrinn. Der Apex der Fruchte zeigt Einkerbungen unterschiedlichen AusmaDes auDer bei B. uuricirluta, bei der die Riinder gleichmiiRig iiber den Griffel verlaufen, weshalb der Apex nicht eingetieft ist. Der Griffel steht aufrecht und bestimmt das unterschiedliche Aussehen der Fruchte sowie die Bestimmung einiger Arten. Andere variable Eigenschaften betreffen den Pedicellus, die Nahte, die valvate Form und die Reife. Die Blutenstinde wechseln zwischen einfacher Traubenform bis zu vielverzweigten Blutenrispen. Die gebogenen Zweige einiger Taxa sind fur eine erste Bestimmung der Art von Bedeutung. Mehrere dieser angefuhrten Eigenschaften sind fur die Klarung der taxonomischen Verwandtschaft wertvoll. Introduction one species complex, B. lnevigatn L., which extends into central Europe. The genus is taxonomically difficult and there is little agreement between the various past taxonomic treatments zyxwvutsrq zyxwvutsrq The genus Biscutelfa L. is widely distributed mainly in the Mediterranean region except for 328 zyx zyxwvuts Feddes Repert., Berlin 103 (1992) 5-6 as to the number of species recognised or the and not fully developed. As much as possible. all ranks of the recognised taxa (e.g. DE CANDOLLE measurements are made on mature fruits a t apI8 1 1, I82 1 ; REICHENBACH 1 829 ; JORDAN1864; proximately similar stage of development and in comCOSSON1872; WILLKOMM & LANGE1880; Rouv parable positions on different plants. At least five fruits per infrutescence were assessed while the total & FOUCAUD 1895; MALINOWSKI 1910; MA- for each taxon ranges from 14 to 60. CHATSCHKI-LAURICH 1926; GUINEA1963; GUIThe length ofeach fruit is measured from the base NEA & HEYWOOD 1964a, b; MAIRE1967 among of the valve to the top while the width is measured others). The major problem encountered in the a t the widest point. Pedicel length is measured from genus is that of specific delimitation. Although the junction with the stem to the base of the stipe. the species usually have characteristic and re- Width measurements are not taken for the pedicel cognizable appearance yet they are very difficult but are referred to using relative terms such as stout to describe precisely. The limits of variation of or slender. The persistent style is measured from the the species are not easy to clarify and define tip of the stigma to the point of contact with the valves. because of intermediate variants that frequently Descriptive statistics of means. standard deviaoccur. There is also the presence of narrow tions and errors are calculated for all variables. endemics which may be morphologically close to other more widespread and better known M o r p h o l o g i c a l e x a m i n a t i o n species. Other problems of the genus have been All fruits are examined by means of a simple hand highlighted in previous papers by OLOWOKUDE-lens and dissecting microscope. The nature of the JO (1985, 1986a, b). fruit apcx and margin are also determined. In this investigation, the fruits and infrutesThe structure and branching patterns of the cences of all species of Biscutella have been infrutescence are determined on fully grown and examined as part of a much wider programme mature plants of each taxon. of research into the systematics of the genus. Cruciferous fruits are extremely diverse and are Results relied upon to a large extent in the classification The basic structure of the fruit in all species of of the family at tribal, generic and specific levels. the genus is similar: it is a stalked, strongly compressed indehiscent didymous silicula (or Materials and methods schizocarpoid) which breaks from the axis into Plant material from three main sources were used for two one-seeded loculi at maturity. The generic this investigation, and these include (a) herbarium name, Biscutella, which means double shield, collections (b) natural populations and (c)cultivated alludes to the peculiar and distinctive fruit samples. resembling a pair of spectacles. The fruit is Herbarium specimens were either borrowed from usually light to deep green when immature but or examined in the following institutions: B, BC, BCC, BCF, BM, G, GDA, GJO, GZU, HBG, K, LINN, turning dark green or light to dark brown or brownish black when fully developed. Some LY, M A , MAF, RNG and W. Abbreviations follow B. megafruits of B. uariegata BOISS.et REUTER, HOLMCREN et al. (1981). carpaeu BOSS et REUTER,B. foliosa MACH.Field studies were conducted in central, eastern and southern Spain where 78 populations comprising LAUR.and B. radicata COSSON are light to deep 14 taxa were investigated and sampled in their natural purple. The infrutescence may consist of a habitats. mixture of mature and immature fruits and Fruits and seeds obtained from the field trips and flowers. Variation in some morphological chathose of known wild origin received from other racters of the fruits is summarised in the Table. collectors and botanic gardens were cultivated in the Representative samples of fruit types are illugreenhouse and experimental plots of the School of strated in Plates I - 111 while the infrutescence Plant Sciences, University of Reading. The plants patterns are shown diagrammatically in the were raised to maturity and studied. Figure. Assessment of fruit characters F r u i t size zyxwvuts zyxwvu zyxwvutsr zyxwvutsrqp zy Fruits are selected from the lower half of the main infrutescence as these are the most typical. Fruits towards the top of the infrutescence are often smaller There is considerable intra- and inter-specific variation in fruit size within the genus (Table). A z $zyxwvutsrq zyxwv - E C i D 4 zyxwvuts zyxw zyx Figure Schematic diagrams of infrutescence patterns in Biscutella A - simple raceme, with erecto-patent pedicels; B - simple raceme, with patent pedicels; C - simple raceme, shaped like a corymb, as in B. ualentinu; D - panicle shaped like a compound corymb; E - compbund raceme or panicle: F - panicle wlth patent branches; G - panicle with flexous branches; H - pyramidal paniculate infrutescence of B. frutescms; I panicle, erecto-patent branches with cauline leaves and bracts; J - panicle. erect branches with c a u l k leaves and bracts; K - profusely branched panicle with cauline leaves and bracts 330 zyx zy zyxwvutsr zyxwv zyxwvutsrqpo zyxwvutsrqponmlkjihgfedcb zyxwvutsrqp zy Feddes Repert., Berlin 103 (1992) 5 - 6 Table Variation in fruit character of Biscutrllu (all measurement in mm f standard error) Taxa Fruit length Fruit width Fruit apex Style length Pedical length 1 1.04 f 0.23 1 1.46 & 0.43 10.15 f 0.70 10.62 f 0.40 10.95 f 0.28 Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Deeply notched Shallowly notched Deeply notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Shallowly notched Not notched Shallowly notched 4.04 f 0.14 4.12 Ifr 0.21 4.00 f 0.31 4.05 i 0.24 3.58 f 0.1 I 3.80 f 0.22 3.35 f 0.12 4.22 k 0.32 4.05 & 0.13 3.28 k 0.17 3.45 & 0.10 3.32 f 0.12 3.40 f 0.18 3.90 f 0.20 5.50 f 0.26 4.52 +_ 0.31 3.00 f 0.1 1 3.34 2 0.21 3.05 f 0.16 3.28 & 0.24 3.45 f 0.17 2.62 i 0.06 2.85 f 0.08 2.44 f 0.14 2.65 f 0.09 2.41 f 0.14 2.62 f 0.18 3.56 f 0.24 3.81 f 0.43 2.56 f 0.24 3.44 f 0.09 3.01 2 0.07 2.81 f 0.08 4.30 f 0.07 2.61 f 0.06 2.54 f 0.12 3.44 f 0.15 4.86 f 0.29 3.38 k 0.14 3.51 f 0.11 3.20 0.06 3.48 f 0.07 3.56 f 0.10 2.28 f 0.09 2.58 f 0.14 3.55 f 0.29 4.70 f 0.18 2.61 f 0.14 3.66 0.21 7.35 0.18 8.66 0.21 8.26 f 0.35 9.75 f 0.63 9.13 f 0.51 7.60 f 0.35 8.33 f 0.31 8.86 f 0.58 9.11 f 0.35 7.25 f 0.25 7.76 0.39 8.17 f 0.74 8.72 f 0.39 7.62 f 0.42 7.76 f 0.41 7.65 f 0.26 9.60 f 0.33 8.42 f 0.37 6.20 f 0.24 7.41 & 0.19 7.80 f 0.26 6.09 f 0.27 6.27 f 0.44 3.75 f 0.13 5.27 f 0.1 1 7.33 f 0.24 7.20 f 0.07 7.31 f 0.12 7.50 f 0.22 8.05 & 0.31 9.18 f 0.1 1 9.01 f 0.23 7.05 f 0.08 7.81 f 0.31 7.04 f 0.12 8.44 f 0.16 7.60 f 0.06 6.82 f 0.23 8.74 f 0.20 8.84 f 0.47 7.48 f 0.22 8.42 f 0.09 8.35 f 0.04 8.00 f 0.11 8.62 f 0.51 7.10 f 0.11 7.48 f 0.20 6.44 f 0.34 8.54 f 0.62 8.44 f 0.36 8.10 f 0.34 6.41 f 0.38 8.15 Ifr 0.23 1 B. ltrei' Ikota subsp. luecigatu 6.30 f 0.18 subsp. illjriccc 7.04 f 0.31 5.58 0.40 subsp. ungust foliu subsp. tirolensis 5.65 f 0.28 subsp. Iitciib 6.55 0.22 5.40 k 0.37 subs;. suhaph~lla 5.62 f 0.29 subsp. oariu subsp. gitrstplirrlic~ir 6.25 & 0.25 subsp. tenrrifdia 5.69 f 0.21 subsp. kerneri 5.61 f 0.38 5.41 f 0.19 subsp. austriircu B. scapiosu 5.09 f 0.12 B.flesuosa 5.36 & 0.22 7.50 f 0.22 B. vuriegatu B. megacurpaeu 10.55 k 0.34 B. foliosu 8.65 f 0.28 5.72 k 0.31 B. greclensis 5.86 k 0.19 B. neusiriuc'ci B.frirtescens 3.84 0.21 B. cincentina 9.73 f 0.33 B. srmpercirens 5.88 f 0.62 3.50 f 0. I 1 B. gluciulis B. hrecijoliu 4.72 & 0.23 5.1 I & 0.19 B. c'uneuta 5.37 & 0.21 B. rutgeyii 5.56 k 0.13 B. lumottii 3.80 f 0.17 B. sclerociirpir B. uraenensis 5.52 f 0.09 6.51 f 0.33 B. diuionensis 5.85 f 0.21 B. confrocersa 6.20 f 0.09 B. brevicairlis 6.02 f 0.05 B. coionopijoliu 6.04 -t 0.14 B. intricata 6.14 & 0.17 B. apricorum 4.60 f 0.08 B. graniticu 6.37 0.13 B. pinnntijida 6.22 f 0.21 B. polyclada 8.96 f 0.44 B. lusitunicu 6.38 f 0.31 B. mediterranea 6.62 f 0.34 B. nicaensis 4.23 f 0.20 B. intermedia 6.48 f 0.51 B. guillonii 4.95 0.14 B. valentina 2.18 0.19 B. microcarpa 3.76 f 0.22 B. baetica 4.82 f 0.31 B. eriocarpa 4.10 f 0.42 B. lyrata 5.68 f 0.19 B. didymu 6.29 f 0.44 B. radicata 8.69 f 1.06 B. auriculata 8.64 f 0.87 B. cichoriifolia +. 2 3 4 5 6 7 8 9 10 1I 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 3I 32 33 34 35 36 37 38 39 40 41 10.60 f 0.40 9.50 f 0.36 10.63 f 0.38 10.40 f 0.42 9.36 f 0.34 9.18 f 0.27 8.94 f 0.31 8.98 f 0.34 10.52 f 0.40 15.00 f 0.78 13.29 f 0.27 8.85 f 0.32 10.37 f 0.24 7.21 f 0.31 17.06 f 0.82 8.95 f 0.71 5.32 f 0.16 7.04 f 0.21 8.35 f 0.20 8.55 f 0.18 8.49 0.1 1 8.21 f 0.22 8.67 f 0.18 10.68 k 0.45 10.74 f 0.32 11.21 f 0.11 11.66 f 0.21 11.45 f 0.1 I 10.51 f 0.09 8.42 f 0.14 11.39 k 0.22 10.48 f 0.37 13.25 f 0.82 10.33 Ifr 0.41 11.62 f 0.70 7.48 f 0.12 11.48 f 0.68 8.55 f 0.19 4.48 k 0.08 7.52 f 0.28 7.82 f 0.37 8.46 f 0.51 10.88 f 0.49 11.90 f 0.52 15.88 f 1.14 13.92 f 0.74 zyxwvut + zyxw * zyxwvutsrqponmlkjihgfed zyxwvut zyxwvutsr zyxwvutsrq zyxwvutsr zyxwvuts J. D. OLowoKuDEjo, Fruits and infrutescences in Biscufella Prominent among species with significant intra-specific variation are B. lusitanica JORDAN in which a large-fruited variant measuring about 9 - l l x 14- 17 mm has been described as a new variety (OLOWOKUDEJO 1986a) or even a species by GUINEA (1963); B. semperuirens L. in which one taxon, var. tornentosa (LAG.) HEYWOOD has silicula measuring 7 - 8 x 12- 13 mm, while the fruits of remaining three yarieties are about 4-6 mm long and 6.5- 10.5 mm wide. The two varieties recognised within B. glacialis (BOISS.& REUTEK) JORDANare also partially distinguishable by their fruit size (OLOWOKUDEJO 1986b). 33 1 coupled with the flattened inner region of tfie valve makes this species very distinctive. The closest to this is found in B. microcarpa but the inner region of the valve are usually convex and not as flat. Style The style is persistent and contributes to the distinctive appearance of the fruit. At the distal end is the capitate or conical stigma which may be bilobed and wider than the style e.g. B. megacarparu (Plate ID), B. irz[crrncdia (Plate IB), B. auriculata (Plate I1 A), B. cichoriifolia (Plate I1 B) and B. microcarpa (Plate I1 D). The stigma may also be much reduced and therefore Fruit apex a n d valve smaller in diameter than the top of the style The apex of the fruit may or may not be e.g. B. frutescens (Plate IA), B. laeviguta subsp. notched. B. auricirlura L. (Plate IlA) is the only guestphalica (Plate I E ) and B. ual~nrina (Plaspecies without a notched apex. In the remai- te M A ) . The style length varies little within and ning taxa the apex is notched to varying extents. between the species. B. auriculuta and B. cichoB. divionensis JORDAN,B. brevicaulis JORDAN riifolia have the longest styles which are about and some specimens of B. intermetlia GOUAN 7.35 mm and 8.66 mm respectively. Within the have deeply notched apices while the remaining remaining taxa the style length varies from taxa usually possess shallowly notched apices 2.28 mrn in B. microcarpu to 5.50 mm in B. megacarpuea (Table). The style is either cylindrical (Table; Plate I A - F). The shape of each of tfie two valves com- or quadrangular in cross section. prising the silicula varies from oval to spherical. Taxa with deeply notched apices always have P e d i c e l oval-shaped valves while those with shallow The fruit pedicel is variable in length and notching usually have spherical valves. Veins thickness. The shortest pedicels are found in occur on the glabrous surface of the valves in B. gfacialis where they hardly exceed 4 - 5 mm some species but vary considerably in their in length while in B. cichoriifolia they may be degree of development and prominence. The as long as 8 -9 mm (Table). The pedicels of venation pattern is conspicuously reticulate on B. auricirlata (Plate IIA) and B. cichoriifolia the valves of B. laevigata L. subsp. lueviguta (Plate IIB) are usually more robust and stout (Plate IC), B. laeuigata L. subsp. guestphalica than those of the remaining species which are MACH.-LAUR. (Plate I E), B. megacarpaea (Pla- generally slender (Plate I). The disposition of te IF), and B. microcarpa (Plate 11D). Embryo pedicels on the infrutescence is also variable; abortion in one of the two valves is a common patent, erecto-patent and erect pedicels may be phenomenon in some species e.g. B. microcarpa found within the genus (Plates 11, Ill). (Plate IlD). The margins of the valve may be very F r u i t i n d u m e n t u m narrow ( <0.3 mm) or fairly wide (>0.5 mm). The fruit margin is diaphanous in B. auriculata Pedicels and valves may be sparsely or densely (Plate 11A) and B. cichoriifolia (Plate I1 B) while hairy or totally glabrous. There is considerable it is membranous in the remaining species. variation in pubescence both within and beB. auriculata is the only species of the genus in tween taxa. The density of hairs on the pedicel which the margins run continuously with the is usually affected by age. A densely hairy pedicel style (Plate IIA). The peripheral region of the at the early fruiting stage may become sparsely valves is swollen and forms a continuous ridge hairy or completely glaborous when the fruit in B. frutescens COSSON(Plate 1A). This feature reaches full maturity. In some populations of zyxwvu 332 zyxwvutsrq zy zyxw Feddes Repert., Berlin 103 (1992) 5 - 6 B. valentina the young pedicels are usually whitish tomentose (Plate IIIA). Simple, uniseriate trichomes which are variously shaped are found on the valves of some species. Some of these are shown in Plates 1-111. This feature is extremely variable both within and between taxa. For example, glabrous and hairy fruits are found within several taxa e.g. B. megacarpaea with hairy (Plate ID), and glabrous (Plate I F ) fruits, B. intermedia (Plate IB); B. auriculata (Plate IIC, E), B. didyma (Plate 111B) and B. lyrata (Plate IIIC, D). This hairs may be clavate, pilose, spinose or papillose. A mixture of any two or more of these hairs may be found on the same fruit surface, as has been reported elsewhere (OLOWOKUDEJQ 1985). Pilose hairs are usually confined to the edges of the valves in B. didyma (Plate 111B) while in B. lyrata the hairs are concentrated on the central and peripheral regions of valves (Plate IIID). However, the intraspecific variability of the hairs makes them unreliable for purposes of identification and classification. Infrutescence B. lamotti JORDAN have long, slender and flexuous infrutescence branches (Fig. 1 G). Although this character is not diagnostic of these taxa, but it is usually confined to them. Moreover, B. frutescens is well characterised by its pyramidal paniculate infrutescence (Fig. 1 H). Cauline leaves o r bracts usually occur at the base of infrutescence branches as shown in Fig. 1E - 1 H, but in B. cichoriifolia (Fig. 1 I) and B. auriculata (Fig. 1J , K) additional cauline leaves or bracts are found on the peduncles. Discussion The preceeding observations show that the basic architecture of Biscutella fruits is remarkably similar in all species of the genus. The peculiar and distinctive fruits thus constitute the most important diagnostic feature for separating the genus from other genera of the family. This is in contrast to the general situation in the Cruciferae which has been described as one of the most difficult families in terms of the delimitation of genera (ROLLIN1938,1959; DAVIS & HEYWOOD1963; AL-SHEHBAZ 1973). Dithyrea is the only genus of the family with a fruit type approaching that of Biscutella but this genus is confined to the New World and also differs from Biscutella in a number of characters which have been elucidated by PAYSON (1918). Although the taxonomic utility of fruit and infrutescence characters within the genus is obscured by the uniformity of certain features in many taxa, yet some species possess several distinctive characteristics that are systematically significant. The extremely small silicula of B. microcarpa and the exceptionally large fruits of B. megacarpaea constitute important distinguishing features. The infrutescence and fruits of B. frutescens are remarkable in the genus for their unique pyramidal shape and swollen margins respectively. This correlates with the distinct anatomical structure of the petiole (OLOWOKUDEJO 1987). The flexuous infrutescence branches of B. sclerocarpa, B. polyclada and B.lamottii can be used for the preliminary identification of these taxa. Other features such as apex, margin and style show taxonomically valuable variation. The deeply notched apices of B. divionensis, and B. brevi- zyxwv zy This is the fruit-bearing portion of the shoot, derived directly from the inflorescence. It is usually terminal and indeterminate. The first fruit to develop is usually the lowest and maturation of the others takes place acropetally. The various patterns of arrangement of the fruits are shown diagrammatically in Fig. 1. The infrutescence may be a simple raceme with either erecto-patent pedicels (Fig. 1 A) o r patent pedicels (Fig. 1B). In some populations of B. valentina, the infrutescence may appear like a simple corymb (Fig. 1 C) or a compound one (Fig. 1D) because of the varying length of the pedicels. The oldest and lowermost flowers usually abort resulting in a compact terminal infrutescence which may even resemble a capitulum. I n most taxa, the infrutescence is a panicle (Fig. 1E - 1K) which may differ in some other features from one species to the other. For example the infrutescences of B. sempervirens var. tomentosa usually have distinctly patent branches which are restricted to the top of the main axis (Fig. 1F). Several specimens of B. sclerocarpa REVEL,B. polyclada JORDAN and zyxwvuts zyxwv J. D. OLOWOKUDEJO. Fruits and infrutescences in Biscurella 333 caulis separate these species from the rest. References B. auriculata is easily recognisable as the only AL-SHEHBAZ, I. A,, 1973, Biosystemaiics of the genus species without a notched apex and with marThelypodium (Cruciferae). Contr. Gray Herb., ’ gins that are excurrent with the style. 204, 3- 148. Moreover, the fruit characters are of great COSSON,E. S. C., 1872, Bull. SOC. Bot. France, 19. assistance in clarifying the relationships of the 222 - 223. component species. For instance, a diagnostic DAVIS,P. H.; HEYWOOD,V. H., 1963, Principles of Angiosperm taxonomy. Edinburgh. combination of stout pedicels, diaphanous marA. P., 1811, Ann. Mus. Nat. Hist. gins, relatively long styles and leafy infrutes- DE CANDOLLE, Paris, 18, 295-301. cences,- reveals the close morphological simiA. P., 1821, Regni vegetabilis systema larity between B. auriculata and B. cirhoriifolia. DE CANDOLLE, Naturale, 2, 407-417. These features, among others, also distinguish GUINEA,E., 1963, El genero Biscuiella. Anal. Inst. these species from other taxa within the genus Bot. Cavanille. 21, 387-405. and support their elevation into a subgeneric GUINEA,E.; HEYWOOD, V. H., 1964, Biscztrella. In: rank as was proposed by OLOWOKUDEJO Flora Europaea, Vol. I./ed. by T. G. TUTINet al. Cambridge. 325 - 330. (1986a). The observed pattern of fruit variaP. K.; KEUKEN, W.; SCHOFIELD, E. K., tion in B. coronopifolia, B. granitica, B. intri- HOLMGREN, 1981, Index herbariorum. Part I . The herbaria of cafa, B. polyclada and B. pinnat fida does not the World. ed. 7. Regnum veg., 106. support the continued separation of these taxa A., 1864, Diagnoses d’especes nouvelles ou (OLOWOKUDEJO 1986b). The random varia- JORDAN, meconnues, Vol. 1. Paris. Leipzig. 292 - 329. tion of fruit features in the various subspecies MACHATSCHKI-LAURICH, B., 1926, Die Arten der of B. laevigata complex shows that the diploid Gattung Biscutella L. sect. Thlaspidiurn (MED.) and tetraploid taxa cannot be separated by fruit DC. Bot. Arch., 13, 1 - 115. size as earlier noted by OLOWOKUDEJO & HEY- MAIRE,R., 1967, Flora de I’Afrique du Nord, Vol. 13, WOOD (1984). Some species, e.g. B. vafentina 126-147. E., 1910, Monographie du genre Biscuand B. sempervirens, which have been shown to MALINOWSKI, rella L. I. Classification et distribution gPograbe widely distributed and highly variable morphique. Bull. Internat. Acad. Sci. Cracovie. CI. phologically (OLOWOKUDEJO 1 9 8 6 d), ~ usuMath.. 1910, I I 1 - 139. ally exhibit wide variations in fruit characOLOWOKUDEJO, J . D., 1985, Scanning electron micteristics. roscopy of fruits in the genus Biscure/la (CrucifeThe presence or absence, and type of indurae). Phytornorphology, 35, 273 - 286. mentum on the fruit valve have formed the basis OLOWOKUDEJO, J . D., I986a, The infrageneric classifor the recognition of many infraspecific taxa fication of Biscutella (Cruciferae). Brittonia, 38, in B. auriculata, B. didyma and B. lyrata (MARE 86 - 88. J. D., 1986b, New nomenclatural 1967; V A N OOSTSTROOM 1970; RAFFAELLI 1985, OLOWOKUDEJO, combinations and three new varieties in the genus 1990). Previous investigation of the fruit surface Biscutel/a (Cruciferae). Feddes Repert., 97, (OLOWOKUDEJO 1985) has revealed the inconsi565 - 570. stency of the micromorphological features and J. D., 1986c, Variation and taxthe variable nature of the indumentum which OLOWOKUDEJO, onomy of Biscutella valenrina in Spain. Can. J. make them unreliable as taxonomic markers. Bot., 64,2965 -2972. ROLLINS(1958) has also demonstrated that the OLOWOKUDUO, J. D., 1986d, Population variation in presence o r absence of hairs in the fruit of Biscutella sempervirens (Cruciferae) in Spain. Dithyrea, a related genus, is a simply inherited Willdenowia, 16, 95- 102. J. D., 1987, Taxonomic value of pecharacteristic under a single gene control and OLOWOKUDEJO, tiole anatomy in the genus Biscutella L. (Crutherefore of no taxonomic significance. zyxwvu zyxwv zyx zyxw zy zyxw Acknowledgements The author wishes to thank the Head of Botany Department, University of Reading, for permission to use the laboratory and greenhouse facilities and the Directors and Curators of herbaria consulted for kindly placing their material at his disposal. ciferae). Bull. Jard. Bot. Natl. Belg., 57, 307 to 320. OLOWOKUDEJO, J. D.; HEYWOOD,V. H., 1984, Cytotaxonomy and breeding system of the genus Biscutella (Cruciferae). Plant. Syst. & Evol., 145, 291 - 309. PAYSON,E. B., 1918, Notes on certain Cruciferae. Ann. Mo. Bot. Card., 5, 143-151. zyx zyxw zyxwvu zyx zyxwv zyxwvut Feddes Repert., Berlin 103 (1992) 5-6 M.. 1985, Taxonomic rearrangement of RAFFAELLI, Biscutella lyraia (Cruciferae). Taxon, 34,695 - 697. RAFFAELLI, M.. 1991. Biscurellu. 1. ser. LJi-arae MALIN.(Cruciferae) in Italia. Discussione sui carattcri morfologici e tassonomia. Webbia, 45. 1-30, REICHENBACH. H. G. L.. 1829, lconographia botanica seu plantae criticae. Vol. VII. Lipsiae. ROLLINS. R. C.. 1938, Smelocskia and Polyctenium. Rhodora. 40. 294- 305. ROLLINS,R. C., 1958, The genetic evolution of a taxonomic character in Ditliyrea (Cruciferae). Rhodora, 60, 145- 152. ROLLINS, R. C., 1959, The genus Syntlzlipsis (Cruciferae). Rhodora, 61, 253 -264. ROY.G.; FOUCAUD, J., 1895. Flore de France. Bd. 2. Paris et Rochefort. 104- 115. VANOOSTSTROOM, S. J., 1970. Adventive Biscirtella’s. Gorteria, 5 , 44-46. WILLKOMM, H . M.; LANCE,J. M. C.. 1880. Prodromus florat: hispanicae. Bd. 3. Stuttgart. 760 to 765. Address of the author: Dr. J. DELEOLOWOKUDEJO, University of Reading, Department of Botany, School of Plant Sciences, Reading RG6 IAS, Great Britain Manuscript received: November, 4th, 1991. Explanafions to Plates I - 111 Plate I Variation of fruits in Bisciriella: (A) B.fruiescen7, silicula with distinctly swollcn margin. (B) B. inierniediu, glabrous and pubescent fruits with shallowly and deeply notched apices. C B. laevigura subsp. luecigutu, glabrous valves with a network of veins. ( D ) B. megucarpueu, big. densely pubescent fruits. (E) B. Iireviguru subsp. guestphalica. glabrous fruit with prominent reticulate venation. (F) B. megucarpaea, glabrous fruit with reticulate venation and well-developed membranous margin zyxwvutsrq Plate I 1 Variation of fruits and infrutescences in Biscutella: (A) B. auriculara, densely pubescent fruit with wide diaphanous margin and stout pedicel. (B) B. cichoriifolia, pubescent fruit with wide diaphanous margin and stout pedicel. (C) B. atrriculuta, portion of infrutescence with patent and erecto-patent, pubescent fruits. (D) B. microcarpa, portion of infrutescence with patent fruits and aborted valves. (E) B. auriculata, portion of infrutescence with patent and erecto-patent glabrous fruits P l a t e 111 Variation of infrutescences in Biscutellu: (A) B. valmiinu, fruits, with pubescent valves and pedicel and terminal flowers. (B) B. didyma, two infrutescence branches with pubescent and glabrous fruits. (C) B. lyratu, glabrous fruit and terminal flowers. (D) B. lyrara, densely pubescent fruits with patent and erectopatent dispositions zyxwvuts J. D. OLOWOKUDEJO, Fruits and infrutescences in Biscutella 335 Plate I 336 zyx zyx zy z Feddes Repert., Berlin 103 (1 992) 5 - 6 zy Plate I1 zyxwvuts J. D. OLOWOKUDEJO, Fruits and infrutescences in Biscziiella 337 zyxwvutsrq Plate 111