Scientific name: Bulbophyllum nigrescens RolfeEnglish name: Vietnamese name: Cầu diệp đen; Lan củ đenOther name:
Short creeping or clustering trunk or branch epiphyte. Rhizome rigid, semi-woody, (2)2.5–3(3.5) mm in diam., with close pseudobulbs, usually touching each other. Pseudobulbs dull greenish, depressed-conical, flattened, (0.8)1–1.6(2) cm in diam., (0.6)0.8–1(1.2) cm tall. Leaf obscurely petiolate; leaf blade coriaceous, lanceolate, (5)6–12(15) cm long, (0.8)1–1.4(1.6) cm wide, tapering into short terete, shallowly grooved petiole-like base, 0.5-1 cm long, obtuse. Inflorescence erect or suberect, long stalked, lax, many flowered secund raceme (16)18-40(45) cm tall; peduncle (10)12–25(30) cm long, straight, glaucous light greenish, with 3-4 (5) small sterile papyraceous scales at the base and (3)4-5 small scarious bracts distant on scape; rachis (4.5)5–12(14) cm long, glabrous, straight or slightly curved, with many to all flowers opening simultaneously. Floral bracts light dull yellowish, papyraceous, narrowly triangular, acuminate, (3)4–5(5.5) mm long, (0.6)0.8-1(1.2) mm wide. Pedicel and ovary (4)4.5-6(7) mm long, ovary obconical, (0.6)0.8-1(1.2) mm in diam. near flower base. Flowers spirally arranged, nodding, turned on one side, not widely opening, 1.2-1.5 cm across. Sepals dull yellowish-green, more or less heavily spotted and striped with brown-purple, spreading, narrowly oblong ovate, (7.5)8-8.5(9) mm long, lateral sepals (3)3.2-3.5(3.8) mm wide, median sepal distinctly narrower, all sepals obtuse, sometimes very shortly apiculate, dorsally glabrous, adaxially densely pubescent throughout with short hairs. Petals almost black, obpyriform spatulate, (1.7)1.8-2(2.2) mm long, (0.6)0.7-0.8(0.9) mm wide, attenuate at the base, broadening and thickening to the triangular, obtuse apex, pubescent throughout apical half and long ciliate along margin. Lip green to greenish, black in apical half, rarely entirely black of dark olive, fusiform, slightly flattened, (5.5)6(6.5) mm long, (1.7)1.8-2(2.2) mm wide, recurved near the base, in basal half with longitudinal green groove and 2 low keels, tomentose throughout with soft hairs, obtuse at apex. Column dull yellowish, shortly cylindric, broad, 1-1.2 mm tall, 1.2-1.4 mm wide, with little protruding stigma and small triangular, acute stelidia; operculum light yellowish to almost white, hemispheric, 0.5-0.6 mm in diam., almost glabrous or finely papillose at apex.
Habitat, phenology and conservation status.
Creeping branch epiphyte. Primary and old secondary broad-leaved evergreen submontane forests on any kind of soils. 900–1500 m. Fl. March – May. Not common.
IUCN Red List status - DD.
Vietnam: Dien Bien (Tua Chua, Tua Thang), Lam Dong (Dalat City area)
Laos: Phongsali (sine loc.) and Xiangkhouang (Kham district, Huad village, Phou Tat Vinh Mt.; Peak district, Huad village, Phou Tat Vinh Mountain) provinces.
S. China?, N. Thailand