Physostigma Balf.

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

Morphology General Habit

Herbs or subshrubs, erect or climbing

Morphology Leaves

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

Morphology Reproductive morphology Inflorescences

Inflorescences either axillary on leafy stems or appearing terminal on leafless shoots, pseudoracemose, many-flowered; rhachis sometimes swollen at the insertion of the pedicels

Morphology Reproductive morphology Flowers

Flowers mostly showy, white to purple

Morphology Reproductive morphology Flowers Calyx

Calyx 5-lobed, 2-lipped, the lower 3 lobes ovate-triangular, the upper pair of lobes united to form an entire or bifid lip

Morphology Reproductive morphology Flowers Corolla

Standard auriculate but without appendages, glabrous; keel with marked basal spur, apex beaked, spirally twisted

Morphology Reproductive morphology Flowers Androecium Stamens

Vexillary stamen free; anthers 5 dorsifixed alternating with 5 basifixed

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary linear, 2–12-ovuled; style long, incurved for over 360°, narrowed below, thickened above, longitudinally barbate near the apex, furnished at the apex above the oblique stigma with a dorsal appendage

Morphology Reproductive morphology Fruits

Pods linear or linear-oblong, often curved, the valves sometimes twisting after dehiscence

Morphology Reproductive morphology Seeds

Seeds large or small, ellipsoid or subcylindrical; hilum linear or elliptic to ovate; aril absent.

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

Note

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).

Placed in subtribe Phaseolinae, in a clade basally branching to Vigna (q.v.) (Thulin et al., 2004)

Habit

Herbs or subshrubs

Ecology

Wet tropical swamp and riverine vegetation, to seasonally dry forest or open woodland and grassland

Distribution

Africa (Guinea-Congolian and Zambezian regions)