Derris monticola (Kurz) Prain

         Lianas. Twigs 3–5 mm diam., striate, glabrous, lenticellate. Leaves with 9–11 leaflets. Stipules ovate-triangular, 2–2.2 x 1.5–1.8 mm, outside sericeous, inside glabrous. Petiole ca. 9.5 cm long, thinly hirsute; rachis ca. 8.5 cm long, thinly hirsute; pulvinus 9–10 mm long. Stipellae absent. Leaflets subcoriaceous; terminal one narrowly obovate, ca. 8.5 x 2.7 cm, length/width ratio ca. 3.2, base narrowly cuneate to attenuate, apex cuspidate, acumen 3–5 mm long, more or less rounded, upper surface glabrous, lower surface thinly sericeous and sometimes glaucous, midrib and veins flat to slightly raised above, raised below, veins 15–18 per side, 3.5–6 mm apart, reaching to near the margin, then curving towards the apex, sometimes anastomosing near the margin, venation reticulate; lateral ones mostly like terminal one, elliptic to narrowly obovate, 6–9 x 2.3–2.5 cm, length/width ratio 2.6–3.6; pulvinus 3–5 mm long. Inflorescences axillary, Pseudoracemes, 12–17 cm long, peduncle 1.7–2.5 cm long, thinly strigose. Bracts subtending brachyblasts ovate-triangular, 1–1.2 x ca. 0.9 mm, outside sericeous, inside glabrous. Brachyblasts knob-like, 1–1.5 mm long with 3–5 flowers throughout, pubescent. Bracts subtending flowers narrowly ovate, 1–1.2 x 0.4–0.7 mm, outside sericeous, inside glabrous. Pedicels 4–4.5 mm long, sericeous. Bracteoles at the base of the calyx, elliptic or ovate, 0.5–0.7 x 0.4–0.5 mm, outside sericeous, inside glabrous. Calyx cup-shaped, 3–3.5 mm high, outside sericeous, inside glabrous, tube ca. 3 mm high; upper lip with 2 short lobes, 0.3–0.4 x 1.8–2 mm; lateral lobes triangular, 0.5–0.7 x 1–1.5 mm; lower lobe triangular, ca. 1 x 1.5–2 mm. Corolla pink or purple (blue according to Thothathri, 1982, but might be not possible). Standard: claw 1.5–2 mm long; blade orbicular or ovate, 10–12 x 8.5–10 mm, apex emarginate, basal callosities indistinct, both sides glabrous. Wings: claw 2.5–2.8 mm long; blade narrowly obovate, 7.3–7.5 x 2.5–2.7 mm, apex rounded, upper auricle 0.5–1 mm long, lateral pocket 1–1.5 mm long, sometimes inconspicuous, both sides slightly sericeous at the apex. Keel petals: claw 2.5–2.8 mm long; blade boat-shaped, 7–7.2 x 3.4–3.5 mm, apex rounded, auricle hardly visible, lateral pocket 1.5–2 mm long, glabrous. Stamens monadelphous, with basal fenestrae, 9–10 mm long, free part of filaments 1–3 mm long, glabrous; anthers 0.5–0.9 x 0.3–0.5 mm, glabrous. Disc annular, 0.2–0.3 mm high, sometimes hardly visible. Ovary hairy, 6–7.5 mm long, stipe indistinct; ovules 4 or 5; style 2.5–4.5 mm long, glabrous but slightly hairy at base. Pods (Thothathri, 1961) narrowly elliptic or strap-like, flat, glabrous, 7–10 x 1.5–2.5 cm, with a wing along both sutures, upper wing wider than lower. Seeds unknown.