白花石豆兰 bai hua shi dou lan

Bulbophyllum riyanum Fukuyama.

Rhizome very short, nearly invisible, covered with several membranous scalelike sheaths; roots fascicular, slender. Pseudobulb absent. Leaves often 3-5 in clusters, nearly secund on rhizome, subsessile; blade elliptic or oblong, 20-35 × 5-8 mm, apex obtuse and retuse. Scapes several, erect, 15-25 mm, slender; raceme often 2-flowered; peduncle slender, base with 2 minute sheaths; floral bracts ovate-lanceolate, 2-3 mm. Pedicel and ovary ca. 5 mm. Flowers erect, pale yellow or whitish, with yellow lip, not fully opening. Dorsal sepal oblong, concave, 4-5.5 × 1.5-2 mm, 3-veined, apex acute; lateral sepals obliquely triangular, 5-6 × ca. 3 mm, base adnate to column foot forming a short mentum, apex acute. Petals oblong-spatulate, very small, 2-3 × 0.6-0.7 mm, 1-veined, entire, obtuse; lip erect, slightly reflexed, narrowly elliptic, ca. 2.5 mm, thinly textured, both surfaces glabrous, 3-veined, base attached to end of column foot, margin entire, apex acute. Column very short, with a foot ca. 2.6 mm; stelidia triangular-acute. Capsule fusiform, ca. 1.1 cm, ca. 3.5 mm in diam. Fl. May-Oct.

● Tree trunks in dense forests; 300-1400 m. E Hainan, E and N Taiwan.