叉唇石斛 cha chun shi hu

Callista flavidula (Ridley ex J. D. Hooker) Kuntze; C. stuposa (Lindley) Kuntze; Dendrobium exsculptum Teijsmann & Binnendijk; D. flavidulum Ridley ex J. D. Hooker; D. pristinum Ames; D. sphegidoglossum H. G. Reichenbach.

Stems cylindric, 5-30 cm, 3-6 mm in diam., lower part narrowed, with 5-17 nodes, internodes 1.5-2.5 cm, with many longitudinal ridges. Leaves narrowly oblong-lanceolate, 4-7.5 × 0.4-1.5(or more) cm, leathery, base with clasping sheath, apex slightly obtuse and hooked on one side. Inflorescence apical on old leafless stem, 1-2.5 cm, 2- or 3-flowered; peduncle 10-15 mm, ca. 1 mm in diam.; rachis thin and soft; basal sheaths 3 or 4, broadly cupular; floral bracts oblong, 5-9 × 2.5-3(or more) mm, papery, obtuse. Pedicel and ovary 0.6-1.1 cm, slender. Flowers small, white. Dorsal sepal oblong, ca. 8 × 3 mm, 5-veined, midvein prominent, apex subacute; lateral sepals obliquely ovate-lanceolate, larger than dorsal sepal, 5-veined, midvein abaxially winged especially below middle, apex subacute; mentum conic, ca. 4 mm. Petals obovate-elliptic, ca. 8 × 3 mm, 5-veined, margin near apex sometimes laxly shortly ciliate, apex obtuse; lip obovate-triangular, ca. 9 mm, base cuneate, apex 3-lobe; lateral lobes ovate-triangular, margin with dense, matted, long white cottony hairs, apex sharply toothed; mid-lobe ovate-triangular, margin similarly hairy, obtuse; disk densely villous, with a broadly keeled rib extending from base to apex, apex thickened. Column short; column teeth triangular, acute.

Epiphytic on tree trunks in open and mountain forests; ca. 1800 m. S Yunnan [Bhutan, NE India, Indonesia, Malaysia, Myanmar, Philippines, Thailand].