疏花石斛 shu hua shi hu

Dendrobium daoense Gagnepain; D. evaginatum Gagnepain; Grastidium daoense (Gagnepain) Rauschert.

Stems ascending or pendulous, cylindric, 30-80 cm, 5-8 mm in diam., unbranched, with many nodes, internodes 3-4.5 cm, pale yellow when dry. Leaves oblong or oblong-lanceolate, 8.5-11 × 1.7-3 cm, leathery, base contracted and dilated into sheaths, apex acuminate or acute; leaf sheath tightly embracing stem, papery, sheath mouth often open when dry. Inflorescence on middle part of old leafy or leafless stems, 1- or 2-flowered; peduncle nearly perpendicular to stem, 1.5-2.5 cm; basal sheaths 3 or 4, tubular, 2-3 mm, membranous; floral bracts ovate-triangular, 6-9 mm, papery, apex obtuse. Pedicel and ovary ca. 2 cm. Flowers fragrant, thinly textured, golden yellow. Dorsal sepal ovate-oblong, 23-30 × 10-12(or more) mm, 7-veined, with many transverse veins, apex obtuse; lateral sepals ovate-lanceolate, 23-30 × 10-12(or more) mm, apex acuminate; mentum broadly conic, ca. 5 mm, apex rounded. Petals slightly obliquely broadly ovate, slightly shorter than sepal, but relatively wide, 7-veined, with many secondary veins, base shortly clawed, apex acute; lip suborbicular, 2-3 cm, base with a claw ca. 3 mm, both sides embracing column, margin irregularly denticulate; disk concave, densely finely papillate. Column ca. 3 mm; anther cap conic, ca. 2 mm, densely finely papillate, front margin ± irregularly serrate.

Epiphytic on tree trunks in mountain forests, lithophytic on damp rocks in mountain valleys; 600-1700 m. C and N Guangxi, SW Guizhou, S Hunan, S Yunnan [Thailand, N Vietnam].

H. P. Wood (Dendrobiums, 640. 2006) tentatively placed Dendrobium henryi in D. sect. Holochrysa.