Bulbophyllum rugosibulbum Summerh.

A small saxicolous herb with a creeping terete rhizome ± 2 mm. in diameter.. Pseudobulbs 2-leaved, narrowly conical to subcylindrical, 1–3.8 cm. long, 0.5–1.3 cm. diameter, obscurely angled, rugose, purplish turning orange-red with age, borne 0.5–1 cm. apart on rhizome.. Leaves coriaceous, narrowly oblong or oblong-elliptic, rounded, 2–5 cm. long, 0.35–1.1 cm. broad.. Inflorescence erect or slightly arcuate, 8–16 cm. long; rhachis terete; peduncle terete, 5–7 cm. long; bracts scarious, distichous, spreading, lanceolate, concave, 4–6 mm. long, 3.5 mm. broad.. Flowers with sepals and petals yellow ± tinged purple, lip purple-brown fringed with yellow-red hairs.. Dorsal sepal ovate, acute, 4.5–6 mm. long, 2–2.5 mm. broad; lateral sepals strongly recurved-deflexed, obliquely ovate, acute, 4–5 mm. long, 2 mm. broad.. Petals linear, subacute, 2 mm. long, 0.5 mm. broad.. Lip linear, fleshy at base, rounded at apex, 4 mm. long, 0.7 mm. broad, long ciliate margins in apical half.. Column fleshy, 1.3 mm. long; stelidia long-acuminate, 1.2 mm. long.. Fig. 67, p. 316.