Woody subshrubs or lianes. Leaves paripinnate; stipules small, usually persistent; stipels minute, filiform; leaflets numerous, opposite, the rhachis projecting beyond the last pair. Inflorescences axillary or terminal, the flowers in fascicles on short reduced branchlets, often arranged unilaterally on the rhachis, or rarely sessile in the axils; bracts and bracteoles present, short save in A. canescens. Flowers small, white, yellow, pink or dark purple. Calyx subtruncate, denticulate or with 5 short teeth, the upper pair partly united. Standard ovate to round, with a short broad claw, glabrous. Stamens 9, joined into a tube split at the apex; vexillary stamen absent; anthers uniform or 4 slightly smaller. Ovary subsessile, many-ovuled; style short, incurved, not bearded; stigma capitate. Pods linear or oblong, subturgid or compressed, more or less septate. Seeds subglobose or ellipsoid and compressed, usually shining, sometimes bright red and black; hilum small, eccentric; rim-aril sometimes developed, usually minute or absent.