Volume 4 > Part 3 > Year 2020 > Page 393 > Leguminosae-Papilionoideae > Derris

2. Derris amoena Benth.wfo-0000185932

in Miq., Pl. Jungh. 2: 252. 1852 & J. Proc. Linn. Soc., Bot. 4 (Suppl.): 110. 1860; Baker in Hook.f., Fl. Brit. India 2(5): 245. 1878; Prain, J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 66(1): 105. 1897; Ridl., Fl. Malay Penins. 1: 597. 1922; Craib, Fl. Siam. 1(3): 487. 1928; Lock & Heald, Legumes Indo-Chine: 87. 1994; Sirich. et al., Syst. Bot. 37: 413. 2012. Plate XXXV: 1–2.

Accepted Name : This is currently accepted.

Synonyms & Citations :

Description : Woody climber; bark maroonish, lenticellate, glabrous; twigs slightly strigose or glabrescent, lenticellate. Stipules triangular, ca 1.5 by 0.7–1 mm, outside thinly sericeous, inside glabrous. Leaves subcoriaceous, reddish when young; petiole 3.5–6 cm long, slightly grooved and striate, glabrous or with few hairs; rachis 3.5–11 cm long, grooved and striate, glabrescent; pulvinus 5–9 mm long, thinly strigose. Leaflets 5–9; petiolules 4–10 mm long; stipels absent; terminal one elliptic to obovate, 6–9 by 3–4.5 cm, apex acuminate, acumen 2–5 mm long, rounded, base cuneate to rounded, upper surface glabrous or slightly strigose, especially at basal part of midrib, lower surface glabrous or slightly strigose, usually glaucous, midrib flat or slightly raised above, veins flat on both sides; lateral veins 7–13 pairs, 2–10 mm apart, parallel, seemingly ending and anastomosing at margin, venation reticulate; lateral ones mostly like terminal one, elliptic to obovate, 4.5–8.5 by 2–4 cm; pulvinus of petiolules 5.5–7 mm long, glabrous. Inflorescences axillary pseudoracemes or pseudopanicles, 7–18 cm long; peduncle 0.5–4.5 cm long, striate, glabrous or sometimes slightly sericeous; bracts subtending brachyblasts ovate to triangular, ca 0.8 by 0.6–0.7 mm, outside sericeous with ciliate margin, inside glabrous; floral bracts ovate, 0.4–0.5 by 0.2–0.5 mm, outside sericeous, inside glabrous. Brachyblasts knob-like, 0.5–0.7 mm long, with 2–7 flowers, sericeous; pedicels 3–7 mm long, sericeous; bracteoles at top or upper part of pedicels, ovate, 0.3–0.4 by 0.2–0.3 mm, outside slightly pubescent, inside glabrous. Calyx cup-shaped, 2–3 mm high, maroonish, outside thinly sericeous, margin ciliate, inside glabrous, tube 2.5–2.8 mm high, upper lip with 2 short lobes, shallowly notched, 0.3–0.4 by 3–4 mm; lateral and lower lobes shortly triangular, 0.5–0.6 by 1.5–2 mm, apex obtuse or rounded. Corolla purplish; standard broadly elliptic to orbicular, 6–6.5 by 8–8.5 mm, apex emarginate, basal callosities absent, outside slightly ciliate at apex, inside glabrous, claw 2.7–3 mm long; wings elliptic, 6–7 by 1.7–2.3 mm, apex rounded, outside slightly hairy and ciliate at apex, inside glabrous, auricle ca 0.5 mm long, claw 1.7–3 mm long; keel boat-shaped, 6–6.5 by ca 3 mm, apex rounded, outside thinly sericeous near apical part and ciliate at apex, inside glabrous, upper auricle indistinct, 0.1–0.2 mm long, lateral pocket 1.2–1.7 mm long, claw ca 2 mm long. Stamens 7–8 mm long, free part of filaments 2–3 mm long, glabrous; anthers ca 0.5 by 0.4 mm, glabrous. Disc indistinct. Ovary 4.5–5 mm long, 2–3-ovuled, thinly sericeous; stipe indistinct; style 3.5–4 mm long, slightly hairy at base or sometimes glabrous. Pods broadly strap-shaped, flat, 4–9.5 by 1.5–2.6 cm, glabrous, with wing along both sutures, upper wing 3–4 mm wide, lower wing ca 2 mm wide. Seeds discoid or bean-shaped, compressed, 9–12 by 7–11 by 1–4 mm; hilum central, ca 1.5 mm long.

Thailand : PENINSULAR: Ranong (Ngao Falls), Surat Thani (Khian Sa), Krabi (Ao Nang), Satun, Songkhla (Khuan Niang, Sadao, Rattaphum).

Distribution : Myanmar (type), Peninsular Malaysia, Sumatra, Borneo.

Ecology : Edge of evergreen forests, along roadsides or rivers, in disturbed areas, in para-rubber (Hevea) plantations or open margins of swamp forests, to 25 m alt. Flowering: December–March; fruiting: February–April.

Vernacular : Yan sao kham (ย่านสาวคำ), yan sao dam (ย่านสาวดำ ), sao dam (สาวดำ), man dam (มันดำ), ya-na-le (ยานะเละ)(Peninsular).