1. Centrosema pubescens Bentham, Comm. Legum. Gen. 55. 1837.
距瓣豆 ju ban dou
Bradburya pubescens (Bentham) Kuntze; B. schiedeana (Schlechtendal) Rose; Centrosema ferrugineum A. Richard; C. intermedium A. Richard; C. molle Martius ex Bentham; C. salzmannii Bentham; C. schiedeanum (Schlechtendal) R. J. Williams & R. J. Clements; Clitoria schiedeana Schlechtendal; Ternatea schiedeana (Schlechtendal) Kuntze.
Herbs, perennial. Stems twining or trailing, sometimes rooting at nodes, slender, villous. Leaves pinnately 3-foliolate; stipules ovate to ovate-lanceolate, 2-3 mm, with longitudinal striations, persistent; petiole 2.5-6 cm; stipels small, setiform; petiolules short, 1-2 mm, terminal one longer; leaflets thinly papery, terminal leaflet elliptic, oblong, or subovate, 2.6-10 × 1.5-6.8 cm, sparsely villous on both surfaces, lateral veins 5-7 on each side, slender, merging near margin, base obtuse or rounded, apex acute; lateral leaflets slightly small, slightly oblique. Raceme with 2-4 flowers near apex; peduncle 2.5-7 cm; bracts similar to stipules in shape; bracteoles broadly ovate to broadly elliptic, obviously striate, adpressed to calyx, larger than bracts. Calyx 5-lobed; upper 2 lobes ± connate, lowest longest, linear. Corolla white, pink, or light purple, 2-3 cm; standard broadly orbicular, densely villous abaxially, with short spur near base; wings falcate-obovate, one side with curved auricle, almost semicircular, each petal shortly clawed. Legume linear, 7-13 × 0.5-0.6 cm, compressed, apex acuminate, beak straight, slender, 8-15 mm; valves convex to ridge from both sutures, twisting at dehiscence. Seeds 7-15, brownish black or yellowish green with dark mottling, oblong, 4-5 mm; hilum short. Fl. Nov-Apr, fr. Jan-Jul. 2n = 22.
Introduced forage plant; near sea level to 100 m. Guangdong, Hainan, Jiangsu, Taiwan, Yunnan [native to Central America (extending to 22° N in Mexico) and South America (Colombia)].
Fantz (Sida 17: 321-332. 1996) showed that the material widely used for herbage and as a green fertilizer by agronomists under the name Centrosema pubescens belongs to two distinct species: the majority to C. molle and the remainder to C. pubescens sensu stricto. However, because the identity of the available Chinese material is not clear, the name C. pubescens is used here in its old, inclusive sense. Wiersema and Kirkbride (Taxon 54: 209-210. 2005) proposed conservation of the name C. pubescens with a conserved type. If this proposal is successful, the correct name for the taxon currently known as C. pubescens sensu stricto will be C. schiedeanum, and that for C. molle will be C. pubescens. There is ongoing debate on the desirability of such a change, and it is possible that the name C. pubescens might instead be rejected to avoid confusion resulting from a change in its correct usage, in which case the name C. schiedeanum would again be correct, while C. molle would remain in use. The two species may be distinguished as follows: C. molle: bracts 4-6 × 1-2 mm, puberulous; pedicels 6-9 mm at anthesis; bracteoles 6-9 × 4-6 mm; seeds brownish black; C. pubescens: bracts 6-9 × 3-6 mm, sericeous; pedicels 3-6 mm at anthesis; bracteoles 10-16 × 6-9 mm; seeds yellowish green.