Neptunia javanica Miq.

Prostrate perennial herb; taproot slender, becoming woody. Stems annual, up to 1 m, terete, compressed or angled when young, sparsely pubescent to glabrous. Stipules persistent, membranous, lanceolate, 2-4 by 0.9-1.5 mm, base obliquely cordate, apex acuminate, caudate, glabrous. Leaves: petiole 0.4-0.8 cm, angled or winged, glabrous or sparsely pubescent, gland usually present in the lower ¾, circular in outline, inconspicuous, less than 1 mm in diameter; rachis 0.9-2.3 cm, angled, prolonged into a leaf-like projection; pinnae 2 or 3 pairs, winged; leaflets 6-17 pairs per pinna, oblong, obtuse to broadly acute, asymmetrical, 2.5-6.1 by 0.9-2 mm, glabrous, margins usually ciliate, surface appearing minutely punctate, lateral veins raised, reticulate (but sometimes indistinct). Inflorescence with peduncle 3-4.5(-5.9) cm, bracts absent; spike short, globular in bud, 8-20-flowered. Lower flowers sterile: calyx campanulate, 5-lobed, green, 0.8-1.3 mm; teeth 0.4-0.7 mm, acute; petals 5, free, 1.6-2.6 mm, green; stamens 10, yellow, sterile, petal-like, 3.8-8 by 0.3-0.5 mm, exserted. Upper flowers bisexual, pentamerous; calyx campanulate, 1.8-2.2 mm, green; teeth acute, 0.4-0.8 mm; petals green, free or coalescent at the margins, 2.9-3.5 mm; stamens 10, 5.3-6.1 mm; filaments slender, white; anthers yellow, 0.7-1 mm, lacking a terminal gland; ovary 1.4-1.8 mm, glabrous, stipitate, style slei ider. Pod subfalcate to falcate, membranous to coriaceous, glabrous, dehiscent along one margin only, 3-4.5 by 0.7-0.8 cm, acuminate at each end, stipitate, stipe 3.8-8 mm. Seeds (5-) 10-16 per pod, situated obliquely on the pod, brown, obovoid, compressed, 3.8-4.8 by 2.5-2.7 mm, areole narrow, open towards the hilum.

It is a tropical plant. They grow in ground or floating in water.