Notes on the genus Argyrolobium (Crotalarieae, Leguminosae), including a new species from southern Africa

S.Afr.J.Bot., 1994, 60(1): 39 - 43

Tribolium is x

39

=

6. Ploidy levels are mostly diploid or sometimes tetraploid in T. hispidum. Alloploidy, tending towards segmental alloploidy, has been determined for the tetraploid T. hispidum. Three of the four species (T. ciliare, T. echinatum and T. utriculosum) are meiotically normal with occasional meiotic abnormalities, indicative of hybridization, present in T. echinatum. Chromosomal behaviour of T. hispidum during meiosis indicates some specimens are hybrids. This is evident from the high percentage of anaphase bridges and other abnormalities observed, since these abnormalities are indications of chromosomal evolution. The four species within this section are morphologically closely related. This is evident from the morphological study during which twenty different characters were studied (Visser & Spies 1994a). This fact is also clearly indicated in the different principal-component analyses. Hybridization is also proven with the segmental alloploid origin for the tetraploid specimens. The morphological study suggests that hybridization is common between T. echinatum and T. hispidum. Occas.ional hybridization between T. hispidum and T. utriculosum is also possible. Since the only significant difference between T. echinatum and T. hispidum lies in their lifespan, we think that both species should be included in a single hybrid swarm, T. echinatum. The number of species in this section should, therefore, be reduced to three, namely T. ciliare, a T. echinatum hybrid swarm and T. utriculosum.

Acknowledgements The University of the Orange Free State and the Foundation for Research Development are thanked for financial assistance during this study.

References ALONSO, L.c. & KIMBER, G. 1981. The analysis of meiosis in hybrids. II. Triploid hybrids. Can . 1. Genet. Cytol. 23: 221 - 234. BELLING, J. 1926. The iron-acetocarmine method of fixing and staining chromosomes. Bioi. Bull. 50: 160 - 162. BOWEN, C.c. 1956. Freezing by liquid carbon dioxide in making slides permanent. Stain Technol. 31: 87 - 90. CARNOY, lB. 1886. La cytodierese de I'oeuf. Cellule 3: 1 - 92. DARLINGTON, C.D. & LA COUR, L.F. 1976. The handling of chromosomes. Allen and Unwin, London. EDWARDS, D. & LEISTNER, O.A. 1971 . A degree reference system for citing biological records in southern Africa. Mitt. bot. StSamml., Munch. 10: 501 - 509. GIBBS RUSSELL, G.E., WATSON, L., KOEKEMOER, M., SMOOK, L., BARKER, N.P., ANDERSON, H.M. & DALLwm, M.l 1990. Grasses of southern Africa Mem. bot. Surv. S. Afr. 58: 1 - 437. KIMBER, G. & ALONSO, L.c. 1981. The analysis of meiosis in hybrids. III. Tetraploid hybrids. Can. J. Genet. Cytol. 23: 235 - 254. SPIES, J.J., DAVIDSE, G. & DU PLESSIS, H. 1992. Cytogenetic studies in the genus Tribolium (Poaceae: Arundineae). Am. 1. Bot. 79: 689 - 700. THOMAS, P.T. 1940. The aceto-carmine method for fruit material. Stain Technol. 15: 167 - 172. VISSER, N.C. & SPIES, J.J. 1994a Cytogenetic studies in the genus Tribolium (poaceae: Danthonieae). I. A taxonomical overview. S. Afr. 1. Bot. (in prep.) VISSER, N.C. & SPIES, J.J. 1994b. Cytogenetic studies in the genus Tribolium (poaceae: Danthonieae). II. A report on embryo sac development, with special reference to the occurrence of apomixis in diploid specimens. S. Afr. J. Bot. 60: 22 - 26.

Notes on the genus Argyrolobium (Crotalarieae, Leguminosae), including a new species from southern Africa T.J. Edwards UN Research Unit for Plant Growth and Development, Department of Botany, University of Natal, P.O. Box 375, Pietermaritzburg, 3200 Republic of South Africa Received 19 July 1993; revised 29 September 1993

A new species, Argyrolobium pseudotuberosum T.J . Edwards, is described and its alliance with other tuberous herbaceous species within the genus is outlined. The taxonomy of A. longifolium (Meissner) Walp. is clarified. 'n Nuwe spesie, Argyrolobium pseudotuberosum T.J. Edwards, word beskryf en sy verwantskap aan ander knolvormige kruidagtige spesies van die genus word geskets. Die taksonomie van A. longifo/ium (Meissner) Walp. word opgeklaar. Keywords:

Argyrolobium, Crotalarieae, Leguminosae, new species, South Africa, taxonomy.

Introduction The occurrence of herbaceous and suffrutescent species with annual stems which develop from thickened subterranean caudices is common in the South African flora. The selective advantage bestowed on such plants relates to the strongly seasonal climates of the subcontinent. Well-developed subterranean caudices are preadaptations to surviving fire and are reported for many members of the Crotalarieae (Edwards & Getliffe Norris 1990; Polhi1l1976; Van Wyk 1991). A number of lineages within Argyrolobium display prominent caudices. These include large suffrutices with annual stems, limited to summer rainfall areas. This group is florally monomorphic and is very similar to Harvey's subsection Race-

mosa (1862) with the exclusion of A. tuberosum Eckl. & Zeyh. Species belonging to this lineage include A. speciosum Eckl. & Zeyh., A. sutherlandii Harv., A . babtisioides (E. Meyer) Walp. and A. longifolium (Meissner) Walp. A second lineage comprises herbs with slender, weakly perennial stems which become morribund after a few seasons. These species occur in both the summer and winter rainfall areas of southern Africa. Some degree of leaf polymorphism is displayed in both groups. However, floral dimorphism is limited to the latter. A. pseudotuberosum T.J. Edwards, described below, belongs within the latter group. In habit it conforms to members of the A. tuberosum alliance, but the fairly complex folding of the standard is reminiscent of the A. longifolium alliance.

40

Argyrolobium pseudotuberosum T.J. Edwards sp. nov. Simile A. tuberoso, sed ab hoc floris flavi cum maculis nigris in vexillo, gemmis apiculatis et plica complexa basalique vexilli differt. TYPE.- South Africa, eastern Transvaal, Lydenburg, Buffelskloof Nature Reserve, in seepage grasslands above the kloof, near the ranger's homestead, Edwards & Burrows 1019 (NU, holotypus). Herb 120 - 600 mm tall, erect, sparingly branched; stems triangular in cross-section, sericeous, becoming glabrous. Leaves

S.-Afr.Tydskr.Plantk., 1994, 60(1) sparsely sericeous; leaflets oblanceolate to narrowly obovate, 20 - 60 X 3 - 8 nun, apex acute, apiculate; petioles 6 - 20 nun long on lower leaves, 2 - 3 nun long above; stipules lanceolate, 8 - 16 X 0.5 - 2 nun. Inflorescence racemose, rarely pseudoumbellate, often lax, 1 - 7 -flowered, terminal, becoming leaf-opposed; peduncle 5 - 50 nun long; bracts narrowly ovate to lanceolate, 5 - 8 X 0.5 - 0.75 nun, bracteoles narrowly ovate to linear, 3 - 6 nun long. Calyx sericeous, deeply bilabiate; upper lip 8.5 - 11 nun long, lobes 5 - 6.5 nun long; lower lip 10 - 12 nun long, lobes 4 - 5.5 nun. Corolla yellow; standard with black flecks in the medial basal region,

Figure 1 Argyrolobium pseudotuberosum. A, habit; B, calyx, inner surface; C, keel; 0, wing, outer surface; E, standard, abaxial surface; F, standard, lateral view. Scale bars: A, 20 mm; B - F, 2 mm.

S.Afr.1.Bot.,1994,60(1) broadly obdeltoid, 9 - 12 X 11 - 13 mm, adaxial surface sparsely sericeous, base canaliculate, claw 2 - 3 mm long; wings oblong to obovate, 9 - 11 X 3 - 6 mm, with lunatelamellate sculpturing in the basal and upper central zones, claw vertical, 2 - 2.5 mm long; keel acutely cymbifonn, 7 - 8 X 4 - 5 mm, claw vertical, 2.5 - 3 mm long. Stamens monadelphous, sheath completely fused above. Ovary 4 - 5 mm long, often laterally glabrous; style 3 - 4 mm long. Fruit sericeous, compressed (only immature fruits seen). Seed not seen. Herbarium specimens of A. pseudotuberosum are easily mistaken for A. tuberosum because flower colour is not preserved

41 in pressed specimens. The flower colour of A . tuberosum is anomalous within the genus; the adaxial surface of the standard is russet while the abaxial surface is creamy yellow. The wing petals are pale basally but are russet distally and the keel is creamy yellow . Flowers of A. pseudotuberosum are consistently lemon yellow with black flecks medially on the standard. While the distributional range of A. tuberosum overlaps with that of the new species, mixed populations have never been recorded. All populations of A. pseudotuberosum have been recorded from hygrophilous grassveld while A. tuberosum is common in drier habitats. (Figures 1 & 3.)

Figure 2 Argyrolobium longifolium. A, flowering branch; B, calyx, inner surface; C, standard, abaxial surface; D, standard, lateral surface; E, ovary, longitudinal section; F, immature androecium showing dimorphic anthers; G, wing, outer surface; H, fruit; I, keel. Scale bars: A & H, 20 mm; B - G & I, 2 mm.

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Material examined TRANSVAAL -2430 (Graskop): Stanley Bush Kop (-DD), P. & C. Raal 1063 (TPA) . -2530 (Lydenburg): Lydenburg (-AB), Wilms 294 (EM); BuffelskloofNat. Res. (-BC), Edwards & Burrows 1019 (NU). NATAL -2729 (Volksrust): Charlestown (-BD) , Wood 5161 (BOL) . -2730 (Vryheid): Naauwhoek, Utrecht (-AD), Devenish 1305 (PRE); Donkerhoek, Devenish 2121 (NU). -2829 (Harrismith): Qudeni Forest (-DC), Edwards 445 (NU). -2830 (Dundee): Mpati Mountain (-AA), Shirley S.n . (NU); Kelvin Grove near Glencoe (-AA), Wood 5138 (MO) . -2930 (Pietermaritzburg): Arnold's Hill near Richmond (-CD), C. Wylie s.n. (NH).

Argyrolobium longifolium (Meissner) Walp., Repertoriurn Botanices Systematicae 2: 844 (1843); Harv.: 69 (1862). Type; Natal, summit of Table Mountain, Krauss 214 (TCD lecto.! selected here; G!, Kl, MO! iso.). Chasrrwne longifolia Meissner: 74 (1843). Argyrolobium natalense Dummer: 272 (1912) synon. nov. Type: Natal , Wood 861 (K lecto.! selected here; BOL!, BM!, K!, PRE!, SAM! iso.). Virgate suffrutex, up to 1.5 m tall, erect, sparingly branched below, well branched above; stems sparsely sericeous, becoming glabrous. Leaves glabrous adaxially, sparsely sericeous abaxially; dimorphic in mature plants, upper leaflets oblanceolate to linear, conduplicate, lower leaflets broadly oblanceolate to elliptic, 30 - 70 X 4 - 16 mm, caducous, apex acute or rounded, apiculate; seedling leaflets suborbicular, 10 - 30 X 8 - 25 mm; petiole 15 - 30 mm long; stipules sericeous abaxially, lanceolate in mature plants, minute in seedlings. Inflorescence racemose, subsecund, up to 20-flowered, terminal, often subtended by axillary inflorescences; bracts linear, up to 6 X 1 mm; bracteoles minute. Calyx sericeous, deeply bilabiate; upper lip incipiently bidentate, 9 - 12 mm long; lower lip 10 14 mm long. Corolla lemon yellow, becoming black in dried specimens; standard 10 - 13 X 10 - 12 mm, suborbicular, adaxial surface sparsely sericeous, base canaliculate, claw 2 3 mm long; wings oblong to obovate, 10 - 12 X 3 - 4.5 mm, with lunate-lamellate sculpturing in the basal and upper central zones, claw vertical, 2 - 3 mm long; keel acutely cymbiform, 7 - 9 X 3 - 4 mm, claw vertical, 2.5 - 3 mm long. Stamens monadelphous, sheath split adaxially. Ovary 9 - 10 mm long;

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style 3 - 4 mm long. Fruit linear, up to 60 X 4 mm, sparsely sericeous, compressed between the seeds. Seed 2 - 3 mm in diameter, slightly compressed. Meissner ' s original description of this species is excellent. However, he overlooked the occurrence of dimorphic anthers, often with flattening of the five short filaments. This, together with the habit and unusual inrolling of the standard base, indicates a close alliance between A. sand.ersonii, A. sutherlandii Harv., A. baptisioides and A. longifolium. On drying, these species tum black. This feature is, however, not unique to the group. Dummer's description of A. natalense has led to confusion. His species concept is based on the 'glabrescent character and more slender racemes' of A. natalense. The current investigation has found no evidence to support the recognition of two species. Raceme stature depends on the part of the plant from which the collection was made - axillary racemes are frequently slender while tenninal racemes tend to be robust. Vestiture in this species is also variable - young growth is invariably hairy whereas mature growth tends to be glabrescent. For these reasons, A. natalense is reduced to synonymy. Examination of herbarium material shows that A. longifolium and A. tuberosum are frequently confused. Live material is easily distinguished on the basis of flower colour and habit. The combination of russet and yellow in fresh flowers of A. tuberosum (discussed under A. pseudotuberosum) is unique within the genus. In addition, A. tuberosum is a slender poorly branched herb seldom exceeding 500 mm in height. Unfortunately, herbarium specimens of A. longifolium are often derived from simple axillary branches which superficially resemble whole plants of A. tuberosum. (Figures 2 & 4.)

Material examined NATAL -2930 (Pietermaritzburg): Dargle (-CA) , Wood 11620 (BOL); summit of Table Mountain, Krauss 214 (G, K, MO, TCD); Camperdown (-DA), Wood 861 (BM, BOL, K, PRE, SAM); Ismont (-DC), Strey 8384 (NU, PRE); Northdene (- DD), Wood 3847 (BM, BOL, MO, SAM); 10 km from Highflats on the road to Umzinto (-AD), Cermishuizen 1805 (PRE).

Acknowledgements Thanks are extended to the cited herbaria for the loan of specimens. The Natal University Research Fund is gratefully acknowledged for financial assistance. Mr. M. Lambert and Ms. C. Ackermann are thanked for their assistance with the Latin and Afrikaans translations, respectively.

S.AfrJ.Bot., 1994,60(1): 43 - 49

43

References

MEISSNER, C.F. 1843. Contributions towards a flora of South Africa Lond. J. Bot. 2: 53 - 105. POLHlLL, R. 1976. Genisteae (Adans.) Benth. and related tribes (Leguminosae). Bot. Syst. 1: 143 - 368. WALPERS, G. 1843. Leguminosae. In: Repertorium botanices systematicae, Vol. 2, pp. 831 - 906. Friedrich Hofmeister, Leiprig. V AN WYK, B.-E. 1991 . A synopsis of the genus Lotononis (Fabaceae: Crotalarieae), ed. A.V. Hall Contr. Bolus Herb. 14: 1 - 292

DOMMER, R.A. 1912. Diagnose Africanae 49. Kew Bull. 270 - 283. EDWARDS, TJ. & GETLIFFE NORRIS, F.M. 1990. Notes on the genus Buchenroedera (Fabaceae) in Natal. S. Afr. J. Bot. 56: 275 -284. HARVEY, W.H. 1862. Leguminosae. In: Rora Capensis, eds. W.H. Harvey & O.W. Sonder, Vol. 2, pp. 1 - 285. Hodges, Smith & Co., Dublin.

Rhus longispina and Rhus pterota, two hitherto confused South African shrubs R.O. Moffett Department of Botany, Qwaqwa Campus, University of the North, Private Bag X13, Phuthaditjhaba, 9866 Republic of South Africa Received 25 June 1993; revised 18 October 1993

Rhus /ongispina Eckl. & Zeyh. and R. pterota Presl are two woody shrubs which are common in the eastern and southern Cape Province. Because of shared habitats and a superficial morphological similarity, these species have been regarded as con specific and known as R. /ongispina for over one hundred and fifty years. A table showing the diagnostic characters separating the two species and a detailed description of each is given, followed by a list of selected specimens indicating their distribution. Rhus /ongispina Eckl. & Zeyh. en R. pterota Presl is !wee houtagtige struike wat algemeen in die oostelike en suidelike Kaapprovinsie voorkom. Omdat hulle habitatte deel en morfologies oppervlakkig ooreenstem, is hierdie twee spesies die afgelope honderd en vyftig jaar as konspesifiek beskou en staan as R. /ongispina bekend. 'n Tabel waarin die diagnostiese kenmerke van die twee spesies uiteengesit word en 'n gedetailleerde beskrywing van elk word voorsien, asook 'n Iys van geselekteerde eksemplare wat hul verspreiding aandui.

Keywords:' Anacardiaceae, Rhus, taxonomy, Cape Province.

Introduction It is generally accepted by botanists that Rhus is a taxonomically difficult genus. Schonland (1930), Burtt Davy (1932) and Fernandes and Fernandes (1966) had difficulty in determining and delimiting the species and many current herbarium taxonomists experience the same problem. In subgenus Thezera (DC) K. Koch, to which the African species belong, Moffett (1993) attributed this to dioecy, minute flowers, lack of mature fruit due to frugivory, and the presence of many putative hybrids. Rhus longispina Eckl. & Zeyh. and R. pterola Presl, collected and described over one hundred and fifty years ago, are among those species which, despite three subsequent taxonomic treatments (Sonder 1860; Engler 1883; Schonland 1930) are still confused today. This, however, is not surprising as Ecklon and Zeyher described and distributed the two species as one, R. longispina, under their number 1116. In some collections, these mixed gatherings were even mounted under one label on the same sheet (Figure 1). A further reason for the confusion is that in the possible type area near Uitenhage, eastern Cape Province, the two species are sympatric and occasionally intermingle in the thorn scrub (Figure 2). When working through the great number of recently collected Drege, Ecklon and Zeyher exsiccatae that had arrived in Europe, Presl of Prague realized that Ecklon & Zeyher 1116 was heterogeneous and described the species with broader winged petioles as Rhus pterota (pteron: Greek for wing) (Presl 1844). Subsequent botanists either did not know of Presl 's publication or chose to ignore it. Rhus pterota had earlier been recognized as an undescribed

species by William Burchell, for on his specimen 4795 which he had collected on 1814-02-18 and which is now in the Kew Herbarium, London, he had written 'Rhus robustum, durum.' In his detailed revision of the South African species of Rhus, Schonland (op. cit.), unaware that he was dealing with two species, understandably produced a confused account of R. longispina. On p.89 he wrote: 'The affinities of this species seem to point to Rh. rigida [(R. rimosa Eckl. & Zeyh.), my parentheses] though it is often placed near Rh. lucida. In some respects it approaches Rh. ciliata Licht. The great variability of this species in the size of leaflets, the length and breadth of petioles is noteworthy, and while in other species of Rhus great variability raises a suspicion of hybridization, such a suspicion cannot be entertained here.' Of the 21 numbered collections cited by Schonland under R. longispina, I have studied 18. Of these 18, 4 are R. longispina, 1 is R. pallens Eckl. & Zeyh., and 13 are R. pterota. Despite their sometimes similar habit and leaf shape, a close morphological examination of Rhus longispina and R. pterota shows that these two species are not closely related and belong to two different groups in the subgenus. R. longispina is related to R. pallens Eckl. & Zeyh. and R. burchellii Sond. ex Engl., whereas R. pterota is related to R. horrida Eckl. & Zeyh. and possibly also to R. problematodes Merxm. & Roessl. A summary of the diagnostic characters of R. longispina and R. pterota is given in Table 1.

Rhus /ongispina Eckl. &. Zeyh., Enumeratio plantarum africae australis 2: 148 (1836) p.p.; Sond.: 520 (1860) p.p.;