Pterolobium R.Br. ex Wight & Arn.

Lianas, climbing shrubs, scramblers, or small trees; branchlets and (main) rachides often armed with recurved, paired or singular prickles. Stipules and stipels small, inconspicuous, caducous. Leaves spiral, bipinnate, petioled; pinnae and pinnules opposite or subopposite, petiolulate. Leaflets many, rather small, opposite or subopposite, subses-sile, slightly emarginate at apex, unequal at base. Inflorescences terminal or axillary, often paniculately aggregated racemes; bracts caducous, bracteoles absent. Flowers bisexual, pedicelled, slightly zygomorphic. Hypanthium shortly cupular or discoid. Calyx lobes 5, imbricate, the lowest (exterior) one concave and larger. Petals 5 (usually 4 similar and 1 different, all similar in P. borneense), imbricate, the standard (superior, interior one) often slightly contracted and the margins slightly inflexed near the middle. Disk obscure or absent. Stamens 10, all fertile, free, in one whorl; filaments usually alternately long and short in buds but equal in length in open flowers; anthers oblong, c. 1 mm long, dorsifixed, introrse. Ovary sessile or stipitate, free, ellipsoid, slightly flattened and curved, 1-or 2-ovuled; style filiform; stigma small, round, truncate or slightly concave. Pods sessile or very shortly stipitate, compressed and samaroid, usually 1-seeded, indehiscent; basal seed-bearing part obliquely or broadly ellipsoid or ovoid; upper, wing-like part, membranous, obliquely more or less oblong or falcate, or elliptic, with slightly transversely curved, obscure or visible veins, one margin thickened and slightly straight, the other thin and slightly convex. Seeds lenticular, flattened, smooth, exalbuminous.