Author: Prain
Morphological description
Liana or straggling shrub up to 20 m high.
Leaves: (densiflorum Pterol compl FM42) petiole and main rachis 12-26 cm long, puberulous, glabrescent; pinnae 4-10(-16) pairs, petiole and rachis 4-8 cm long, puberulous. Leaflets 8-12 pairs per pinna, oblong, 8-13 by 3.5-4 mm, entire, nerves and veins invisible.
Inflorescences 16-30 cm long, densely flowered, rachis and branches puberulous, glabrescent; pedicels 5-6 mm.
Flower : (densiflorum Pterol fl FM42 )Hypanthium c. 1 mm high, sparsely puberulous. Calyx lobes oblong or oblong-ovate, c. 4 by 2 mm, sparsely puberulous outside and ciliate on the margins. Petals : standard slightly oblong or oblanceolate, slightly thicker than the others, margins inflexed near the central part, glabrous outside, puberulous on the central part inside; the others oblanceolate, c. 4 by 1 mm, puberulous at the base inside and on the basal margins. Stamens : filaments 4-7 mm, lower 1/3-2/3 hairy; anthers c. 1 mm long. Ovary sessile, c. 2 mm long, glabrous or sparsely puberulous on placental side, 2- or 1-ovuled; style 5-7 mm.
Pods not stipitate; seed-bearing part broadly ellipsoid or suborbicular, 1.6-2 by 1.2-1.8 cm, glabrous, reticulate; wing 5-5.6 by 1.3-1.8 cm, the basal part gradually narrowed along the lateral side of the seed-bearing part towards almost its base (densiflorum Pterol compl FM42).
Seeds c. 8 by 7 mm.
Distribution
Malesia : Sumatra (Aceh, Tapianuli), Malay Peninsula (Selangor, Malacca, and Penang I.).
Habitat
In lowland forest, disturbed forest, hill side, once recorded occurring in mesotrophic forest over craggy limestone with deep soil pockets (FRI 15635), up to 400 m altitude