Home
Vines or herbs, rarely shrubby, mostly with sturdy rootstocks, lacking unci-nate hairs. Leaves pinnate or subdigitate trifoliolate, rarely 1-foliate, mostly en-tire; stipels, nervate, mostly blunt; glabrate stipules sometimes produced below the insertion, sometimes bilobate. Inflorescences axillary or terminal, pseudor-acemes or subcapitate, the rachis contracted, the nodes glandular; bracts and bracteoles caducous; pedicels 1-2 per node, mostly shorter than the calyx. Flow-ers yellowish or white, sometimes with some purple or violet; calyx 2 lipped, the upper lip emarginate, the lowest tooth of the lower lip longest; standard orbicular, auriculate, sometimes appendaged on the dorsal face, the wings about equalling the standard and keel, the keel apically curved up to 1 spiral, often oblique; vexillary stamen free, the anthers uniform; style apically thickened and barbate on the inner face, caducous, sometimes with a curved beak. Legume linear to oblong, turgid or compressed, straight or curved, not septate; seeds reniform or quadrate, the hilum short or long, a well developed aril sometimes present. Vigna embraces about 150 species of tropical regions of both hemispheres. In Panama most species have flowers at least partly yellow, but in other countries some species have violet or purple flowers. A number of species of Vigna are important food plants for man, e.g. V. unguiculata, and species are sometimes cultivated for cattle fodder.
Corolla small or medium-sized, yellow, blue or purple inside (internal face of standard, external face of wings), greenish outside (external face of standard), all petals of subequal length; standard glabrous (except in V. heterophylla), emarginate, usually slightly wider than long and symmetrical, with inflexed auricles and appendages on the internal face, less often without appendages; appendages of the standard are based on a U-shaped pattern with one on each half of the standard, but the pattern is rarely complete; it can be reduced to the central part of the U with the appendages appearing parallel and very close together (central position), or sometimes joined and appearing V-or X-shaped (V.luteola or V. monophylla for example); it can be reduced to the lateral part of the U with the appendages appearing parallel but spaced apart (lateral position) (as in V. unguiculata); it can be reduced to the basal part of the U with the appendages appearing perpendicular to the standard axis (V. comosa); keel whitish except for the beak (if there is a beak), usually fused on the upper side, truncate, obtuse or conspicuously beaked, sometimes the beak incurved through up to 180° (V. radiata), sometimes with a distinct conical pocket on the left-hand petal (V. vexillata for example).
Twining or erect herbs, rarely subshrubs. Leaves pinnately 3-foliolate; stipules peltate or basally spurred, 2-lobed, cordate, or truncate. Racemes axillary or terminal, nodes of rachis often thickened and glandular. Bracts and bracteoles deciduous. Calyx 5-toothed, 2-lipped. Corolla yellow, blue, or purple; standard suborbicular, base appendaged; wings shorter than standard; keel subequal to wings, incurved, not beaked or produced into an incurved or spirally twisted beak. Stamens diadelphous; anthers uniform. Ovary sessile; style filiform, upper part thickened, bearded or hirsute lengthwise inside; stigma oblique. Legumes linear or linear-oblong, terete or flat. Seeds reniform or subquadrate; hilum short or elongate, with or without aril.
Inflorescence axillary, falsely racemose or flowers in dense 1–many-flowered subumbellate clusters or fasciculate; rhachis thickened and glandular at the point of insertion of the pedicels, flowers paired at each node; bracts and bracteoles deciduous, usually similar in shape and nervation; pedicel shorter than or as long as the calyx, extending or not as the pod matures.
Ovary 1–many-ovuled; style with tenuous lower part obsolete to quite long, filiform or flattened, upper part thickened and cartilaginous, straight or curved, upper portion barbate or hirsute on the internal face, produced beyond the stigma to form a short to long subulate beak (except in subgenus Haydonia); stigma completely lateral or oblique.
Leaves pinnately, more rarely subdigitately, 3-foliolate, 1-foliolate or simple; leaflets entire, venation usually reticulate, rarely with secondary nerves parallel (V. multinervis) or tertiary nerves parallel; stipules usually bilobed or spurred at the base, sometimes peltate, rarely truncate; stipels persistent, rarely absent.
Seeds mostly reniform or quadrate, thickness usually slightly less than width, usually cream-coloured, cream-coloured in combination with grey, mottled and speckled patterns, or black; hilum small or elongate; aril obsolete to well developed, usually excentric, often 3-pronged.
Pods linear or linear-oblong, usually terete, rarely flattened (V. macrorhyncha), with sutures not raised (except V. macrorhyncha), straight or curved, not septate (seeds are separated by a spongy tissue, not as woody as in Dysolobium and Pachyrhizus); style caducous.
Vexillary stamen free; 5 shorter filaments (including the vexillary one) sometimes with a pair of joined glands below each anther (in subgenus Haydonia); anthers uniform.
Climbing, twining, prostrate or erect herbs or subshrubs, rarely small shrubs, mostly from woody or tuberous rootstocks, without hooked hairs (as in Phaseolus).
Calyx 5-lobed, 2-lipped; lower lip 3-lobed, the middle lobe usually the longest; upper lip of 2 lobes completely or partly united.
Pollen triporate, exine coarsely reticulate (except in subgenus Haydonia).
