Derris elliptica (Wall.) Benth.

         Lianas, up to 5 m high. Bark dull greenish to brown. Twigs 4–15 mm diam., hirsute, glabrescent in older parts, lenticellate. Stipules triangular or ovate, 3–3.5 by 1.7–3 mm, outside sericeous, inside glabrous. Leaves with 7–15 leaflets; petiole 4–14.5 cm long, striate, (thinly) hirsute; rachis 6–20.5 cm long, striate, (thinly) hirsute; pulvinus 5–11 mm long, (thinly) hirsute. Stipellae rarely present, acicular, ca. 1.5 mm long. Leaflets chartaceous to subcoriaceous, terminal one obovate to narrowly obovate, 7–16 by 2–5 cm, length/width ratio 3.2–4.3, base cuneate, apex acuminate, acumen 3–20 mm long, rounded, upper surface glabrous to thinly sericeous, lower surface more or less sericeous, older leaflets often less hairy, midrib flat above, rarely slightly sunken, raised below, nerves flat above, raised below, 7–14 per side, 3–16 mm apart, curving towards the apex and almost reaching the margin, sometimes anastomosing near the margin, venation reticulate; lateral leaflets mostly like terminal one, narrowly elliptic to obovate, 4–16 by 2–5.5 cm, length/width ratio 2–4; pulvinus 3–7 mm long, (thinly) sericeous. Inflorescences axillary pseudoracemes/ pseudopanicles, rarely terminal, up to 30 cm long; peduncle 0.5–5.5 cm long, sericeous; lateral branches 5–20 cm long. Bracts subtending brachyblasts ovate to triangular, 1.5–2.5 by 1–1.5 mm, outside sericeous, inside glabrous; bracts subtending flowers ovate, elliptic, triangular or cordate, 1.5–2.5 by 1–2 mm, outside sericeous, inside glabrous. Brachyblasts long cylindrical, 10–25 mm long, with 2 or 3 flowers at the apex. Pedicels 5–11 mm long, sericeous. Bracteoles at the top of the pedicels, (narrowly) ovate or triangular, 1–2.7 by 1–2 mm, outside sericeous, inside glabrous. Calyx 5.5–7 mm high, brown to dark maroonish, outside sericeous, inside sericeous at apex, tube 4–6 mm high; upper lip hardly visible or sometimes with 2 short semicircular lobes; lateral lobes (broadly) triangular, 1–1.5 by 3–5 mm; lower lobe triangular, 1.5–2.5 by 3–5mm. Corolla pale to deep pink, standard with green blotch at base. Standard: claw 3–4 mm long; blade orbicular, 12–17 by 10–17 mm, apex emarginate, basal callosities large, outside sericeous, except for the margin and claw, inside sericeous at apex. Wings: claw 4.5–5 mm long; blade obliquely elliptic, 10–13 by 4.5–5 mm, apex rounded, upper auricle 0.5–1 mm long, lower auricle absent, lateral pocket 2–5 mm long, sometimes hardly visible, outside with some hairs at the ventral side part of the apex, inside sericeous at apex. Keel petals: claw 4.8–5 mm long; blade boat-shaped, 10–11 by 5–6 mm, apex rounded, auricle indistinct, lateral pocket large, 4–5 mm long, outside with some hairs at apex, inside sericeous at apex, rarely with some hairs at the apex. Stamens monadelphous, with basal fenestrae, 14–23 mm long, free part 3–7 mm long, glabrous, rarely with some hairs; anthers 0.3–0.6 by 0.2–0.4 mm, with some hairs outside. Disc indistinct, annular, usually with some hairs. Ovary 6–10 mm long, outside sericeous, inside with a row of hairs along the lower suture; stipe 1–1.7 mm long, sericeous; ovules 3–5; style 8–14 mm long, sericeous in lower part. Pods elliptic or strap-like, flat, 4–11 by 1.5–2 cm, thinly sericeous, sometimes also glaucous, with wing along the upper suture only or rarely winged on both sutures, upper wing 1.5–2 mm wide, lower wing usually undeveloped, up to 1.5 mm wide; seed chamber absent. Seeds seen immature in well-developed pods, bean-shaped, flat, ca. 13 by 8–8.5 by ca. 3 mm; hilum central, 2.5–3 mm long.