Derris glabra Sirich.

         Lianas, basal diameter ca. 5–10 cm. Twigs 3–8 mm diam., lenticellate, glabrous, striate. Stipules triangular, 1–1.1 by 9–1.1 mm, caducous, outside thinly sericeous, margin ciliate, inside glabrous. Leaves with 3–5 leaflets; petiole 2.5–5 cm long, striate, glabrous; rachis 0.7–2.5 cm long, striate, glabrous; pulvinus 4–6 mm long, glabrous. Stipellae absent. Leaflets subcoriaceous; terminal one (broadly) elliptic, 6.5–9.5 by 3.4–5.8 cm, length/width ratio 1.6–1.9, base obtuse, apex acuminate, acumen 5–6 mm long, rounded or slightly emarginate, upper and lower surface glabrous, midrib distinct, pale, flat above, distinctly raised below, veins slightly raised above and below, 4–6 per side, 7–15 mm apart, not reaching the margin but curving towards the apex, sometimes anastomosing near the margin, venation reticulate; lateral ones mostly like terminal one but usually smaller, elliptic to ovate, 4.5–5.5 by 2.5–3.8 cm, length/width ratio 1.4–1.8; pulvinus 4–6 mm long, glabrous. Inflorescences axillary or terminal pseudoracemes/ pseudopanicles, 12.5–28 cm long; peduncle 10–15 mm long, glabrous; lateral branches 2.5–17 cm long. Bracts subtending brachyblasts ovate, 0.9–1 by 0.4–0.5 mm, outside glabrous or with some hairs at the base, margin ciliate, inside glabrous; bracts subtending flowers ovate, 0.6–0.7 by 0.4–0.5 mm, glabrous on both sides, margin ciliate. Brachyblasts knob-like to elongated cylindrical, 1–11 mm long with 2–5 flowers throughout, glabrous or with few scattered hairs. Pedicels 3–4 mm long, glabrous or with some scattered hairs. Bracteoles at the apex of pedicels, elliptic to ovate, 0.5–0.6 by 0.2–0.4 mm, glabrous on both sides, margin ciliate. Flowers slightly fragrant. Calyx reddish-green, cup-shaped, 2.7–3.2 mm high, outside glabrous, margin ciliate, inside glabrous or thinly sericeous in the apical part, tube 2.5–2.7 mm high, upper lip, 0.3–0.5 by 2.3–2.5 mm; lateral lobes triangular or semi-circular, 0.3–0.5 by 1.7–2 mm; lower lobe triangular or semi-circular, 0.3–0.5 by 1.5–1.6 mm. Corolla whitish or with pale pinkish hue at the top. Standard: claw 2.7–3 mm long; blade broadly obovate to orbicular, 6.5–7 by 7–8 mm, apex emarginate, basal callosities absent, glabrous. Wings: claw 2.7–3 mm long; blade elliptic, 5.6–6 by 1.8–2 mm, apex rounded, upper auricle 0.5–1.2 mm long, lower auricle indistinct, both sides glabrous. Keel petals: claw 2.7–3 mm long; blade boat-shaped, 5.5–6 by 3–3.5 mm, apex rounded, upper auricle 0.4–0.7 mm long, lateral pocket ca. 1.5 mm long, sometimes hardly visible, both sides glabrous or with some hairs at apex. Stamens 10, monadelphous with basal fenestrae, 8–9 mm long, free part 2–2.5 mm long, glabrous; anthers ca. 0.5 by 0.4–0.6 mm, glabrous. Disc annular or indistinct, 0.2–0.5 mm high, glabrous. Ovary 5.5–6 mm long, thinly strigose, stipe indistinct; ovules usually 3; style 3.5–4 mm long, glabrous. Pods strap-like, 7–10 by 1.5–2 cm, glabrous, with a wing along both sutures, upper wing 3–5 mm wide, lower wing 3–4 mm wide; usually become mature with undeveloped seed(s); seed chamber absent. Seeds 1–2 per fruit, discoid, flat, 17–20 by 10–15 by 1–2 mm; hilum central, 1–1.4 mm long.