Centrosema (DC.) Benth.

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

Habit

Herbs or subshrubs

Ecology

Tropical and subtropical bushland formations derived from seasonal forest, woodland, wooded grassland and shrubland, also forest margins

Distribution

S America (most spp. in Brazil), C America, Caribbean, Mexico and SE USA; 3 spp. widely introduced in the Old World

Note

Placed in subtribe Clitoriinae (see comments under Clitoria)

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).

Leguminosae, B. Mackinder, R. Pasquet, R. Polhill & B. Verdcourt. Flora Zambesiaca 3:5. 2001

Morphology General Habit

Climbing herbs or subshrubs.

Morphology Leaves

Leaves pinnately 3-foliolate in the Flora Zambesiaca area, elsewhere (1)3(7)-foliolate; stipules small, striate; stipels present.

Morphology Reproductive morphology Inflorescences

Inflorescences (1)few–many-flowered, falsely racemose; bracts paired, striate; bracteoles appressed to the calyx, striate.

Morphology Reproductive morphology Flowers Calyx

Calyx 5-lobed, the upper pair largely joined into a bifid lip.

Morphology Reproductive morphology Flowers Corolla

Corolla showy; standard broad, with a conspicuous spur on the back above the claw, often pubescent outside.

Morphology Reproductive morphology Flowers Androecium Stamens

Vexillary filament free or joined to the others at the base.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary linear, many-ovuled; style curved, flattened and slightly widened towards the terminal stigma, pubescent or bearded at the apex.

Morphology Reproductive morphology Fruits

Pod linear, with 4 raised nerves or wings, dehiscent.

Morphology Reproductive morphology Seeds

Seeds variously coloured, oblong or ellipsoid, with an elliptic to linear hilum.