Author: (Linnaeus) Irwin & Barneby
Morphological description
Herb or small shrub up to 60(-100) cm, sticky through viscid bristles.
Leaves with 2 pairs of leaflets (absus Cham Ic Nees t350 det ); stipules linear, acute, 2-4 mm; petiole viscid-bristly, 2.5-3.5 cm; rachis 5-8 mm with a tiny, 0.5 mm long, ligulate-acute gland between each pair of leaflets. Leaflets subsessile, membranous, very unequal-sided, ovate-lanceolate, 2-3 by 1-2 cm, apex rounded or acute, base rounded or cuneate; puberulous or pubescent on both surfaces.
Inflorescence: Racemes terminal or axillary, 4-12 cm long, lax-flowered, shortly pedunculate; bracts ovate-auriculate, 2 mm; bracteoles very small; pedicels 3-4 mm, velutinous.
Flowers: Sepals narrowly ovate, 3-4 mm, with glandular hairs outside. Petals yellow turning brick-red, obovate, subequal, 5-7 mm, claw short. Stamens 5, subequal; filaments c. 2 mm; anthers 1-2 mm, with lateral rims opening at apex and gradually downwards to the base; staminodes absent. Ovary densely strigose; style glabrous; stigma spathulate, recurved, ciliate (absus Cham Ic Nees t350 det ).
Pods flat, on a 5 mm long stalk; strap-shaped, 4-5 by 0.7-0.8 cm (absus Cham Ic Nees t350 det ).
Seeds 5-8, ovate, flattish, 3-4 mm.
Distribution
Of palaeotropic origin; in Malesia, however, introduced and only locally common, e. g., in Java, Bali, Timor and Celebes. It was also collected from Penang I. in the north and scattered on the Malay Peninsula; also recorded from New Guinea.
Habitat & Ecology
A weed in open, sunny places up to 900 m altitude; on open soil in eroded areas, old lava streams, waysides, along railroads; according to De Wit (1956: 279) it is a conspicuous element in the spring flora on the W Baluran savannas in E Java.