Sphenostylis E.Mey.

Leguminosae, J. B. Gillett, R. M. Polhill & B. Verdcourt. Flora of Tropical East Africa. 1971

Morphology General Habit

Herbs or subshrubs, prostrate, climbing or erect

Morphology Leaves

Leaves pinnately 3-foliolate; stipules not spurred, persistent; stipels present

Morphology Reproductive morphology Inflorescences

Inflorescences axillary, falsely racemose, few-many-flowered; rhachis thickened at the insertion of the pedicels

Morphology Reproductive morphology Flowers Calyx

Calyx 5-lobed, short, 2-lipped, the lower lip of 3 obtuse lobes, the upper pair of lobes completely or almost completely joined to form a small rounded or emarginate lip

Morphology Reproductive morphology Flowers Corolla

Corolla small or medium-sized, yellow, blue or reddish; standard rounded, auriculate but without appendages, glabrous

Morphology Reproductive morphology Flowers Androecium Stamens

Vexillary stamen-filament free and dilated at the base; 5 dorsifixed anthers alternating with 5 basifixed anthers

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary linear, many-ovuled; style ± twisted, thickened basally, thinning near the middle and then enlarged, flattened and spatulate at the apex, pubescent inside and along the margins; stigma terminal

Morphology Reproductive morphology Fruits

Pods linear, compressed, 5-many-seeded, ± septate between the seeds, the style often persistent

Morphology Reproductive morphology Seeds

Seeds cylindrical or ellipsoid; aril not developed.

Legumes of the World. Edited by G. Lewis, B. Schrire, B. MacKinder & M. Lock. Royal Botanic Gardens, Kew. (2005)

Habit

Herbs or subshrubs

Ecology

Seasonally dry tropical and subtropical open forest, woodland, bushland and thicket, wooded grassland and grassland

Distribution

Africa (mainly Zambezian and Sudanian regions)

Note

Placed in subtribe Phaseolinae; basally branching in the Macrotyloma-Dolichos-Nesphostylis clade (Thulin et al., 2004)

Previous accounts of the Phaseoleae by Baudet (1978) and Lackey (1981) recognised 90 and 84 genera and c. 1540 and 1480 species respectively in the tribe. In an equivalent, i.e. traditionally held view of Phaseoleae, 89 genera and (1554)–1567–(1580) species are treated here (Table 9; Fig. 47). Changes between Baudet (1978) and this treatment are that eleven genera are now in synonymy or have subsequently been placed in Millettieae, two genera have been transferred from Desmodieae and eight new genera have been added. Vigna has traditionally been thought to comprise some 150–200 species, but Vigna sens. strict. may contain fewer than 100.

Recent molecular analyses of the tribe, however, have emphasised both the polyphyletic and paraphyletic nature of Phaseoleae as traditionally circumscribed (Bruneau & Doyle, 1990; Doyle & Doyle, 1993; Delgado Salinas et al., 1993; Bruneau et al., 1995; Doyle et al., 1997, 2000; Kajita et al., 2001; Goel et al., 2001; Lee & Hymowitz, 2001). This has required a radical realignment of elements of the phaseoloids (Table 9; Fig. 47), with at least two major clades being evident: Phaseoleae subtribes Diocleinae and Ophrestiinae which together with tribe Abreae are allied to the core-Millettieae (Fig. 45), and the remaining groups comprising a Phaseoleae sens. lat. clade. The rbcL phylogeny of Kajita et al. (2001) and the ITS analysis of Hu et al. (2002) are equivocal as to which clade subtribe Clitoriinae belongs. Phaseoleae sens. lat. also includes two traditionally independent tribes, the Desmodieae and Psoraleeae. Delimiting a recircumscribed Phaseoleae sens. strict is thus very problematic. A solution may be to recognise a broad tribe Phaseoleae, comprising the subtribes Kennediinae, Cajaninae, Phaseolinae and Glycininae, assorted basally branching genera, and tribes Desmodieae and Psoraleeae (both treated at subtribal level).