Derris alborubra Hemsl.

         Lianas, basal diameter 5–10 cm. Twigs 3–4 mm diam., glabrous, lenticellate. Stipules triangular, ca. 1.5 by 1.3–1.5 mm, outside thinly sericeous, inside glabrous. Leaves with 3–7 leaflets, reddish or brownish when young; petiole 2–4.5 cm long, grooved and striate, thinly sericeous or nearly glabrous; rachis 3.5–5 cm long, (slightly) grooved above, sericeous, especially in the groove; pulvinus ca. 5 mm long, thinly sericeous. Stipellae absent. Leaflets subcoriaceous to coriaceous; terminal one elliptic, 7–8 by ca. 3 cm, length/width ratio 2.3–2.6, base cuneate, obtuse to rounded, apex obtuse and slightly emarginate, upper surface shiny, glabrous but strigose along midrib, lower surface thinly strigose, midrib slightly raised in a furrow above, veins slightly raised above, 7–10 per side, 5–8 mm apart, not reaching the margin but curving towards the apex, sometimes anastomosing near the margin, venation reticulate; lateral ones mostly like terminal one, elliptic, 6.5–8 by 2–3 cm, length/width ratio 2.6–3; pulvinus 2–3 mm long, (thinly) sericeous. Inflorescences axillary or terminal, mixed forms between panicles and pseudoracemes/ pseudopanicles, up to 30 cm long, peduncle 5–35 mm long, sericeous; lateral branches up to 15 cm long, becoming shorter upwards and near the apex only brachyblasts. Bracts subtending brachyblasts (or lateral branches) triangular to narrowly triangular, 1.3–1.8 by 0.6–0.8 mm, outside sericeous, inside glabrous; bracts subtending flowers ovate to triangular, 0.7–0.8 by 0.5–0.6 mm, outside sericeous, inside glabrous. Brachyblasts cylindrical, 1.5–3 mm long, with 3–5 flowers, sericeous. Pedicels 3–5 mm long, sericeous. Bracteoles at the top of the pedicels, triangular, ca. 0.7 by 0.3–0.4 mm, outside sericeous, inside glabrous. Calyx maroonish, cup-shaped, 4–4.2 mm high, outside sericeous, margin ciliate, inside glabrous, tube 2.7–3 mm high, upper lip with 2 short triangular lobes, 0.3–0.5 by 1.5–2 mm; lateral lobes triangular, 1–1.3 by 3.5–4 mm; lower lobe triangular, 1–1.3 by 1.7–2 mm. Corolla pure white. Standard: claw 2.5–3 mm long; blade broadly obovate to orbicular, 8–10 by 7–8 mm, apex emarginate, basal callosities absent, outside thinly pubescent at apex, sometimes glabrescent, inside glabrous. Wings: claw 3–4 mm long; blade elliptic, 8–8.5 by 1.3–1.5 mm, apex rounded, outside glabrous or thinly ciliate at apex, inside glabrous, upper auricle 0.7–1 mm long, lower auricle indistinct, 0.1–0.3 mm long. Keel petals: claw ca. 3 mm long; blade boat-shaped, 6.5–8 by 3–3.5 mm, apex rounded, outside glabrous or thinly ciliate at apex, inside glabrous, upper auricle 1–1.5 mm long, lateral pocket hardly visible. Stamens monadelphous, with basal fenestrae, 10.5–11 mm long, free part 2–3 mm long, glabrous; anthers ca. 0.4 by 0.3 mm, glabrous. Disc shortly tubular, more or less distinctly (5- or) 10-lobed, up to 0.6 mm high. Ovary 6.5–7 mm long, stipe indistinct, sericeous; ovules 4 or 5; style 3–4 mm long, thinly hairy at base. Pods elliptic to discoid or obovoid, 2–4 by 2.2–2.5 cm, with few hairs especially at the base and the beak, sometimes glabrous, winged along both sutures, upper wing 4–5 mm wide, lower wing ca. 2 mm wide; seed chamber absent. Seeds 1 per fruit, discoid, flat, 7–8 by 6–7.5 by ca. 1 mm; hilum central, 1–1.3 mm long