10. Dendrobium chrysotoxum Lindley, Edwards’s Bot. Reg. 33: ad t. 19. 1847.
鼓槌石斛 gu chui shi hu
Callista chrysotoxa (Lindley) Kuntze; Dendrobium chrysotoxum var. delacourii Gagnepain.
Stem pseudobulbous, erect, fusiform, 6-30 cm, 1.5-5 cm in diam. at middle, with 2-5 internodes, with many bluntly rounded ridges, golden yellow when dry. Leaves 2-5, subterminal, oblong, to 19 × 2-3.5 cm or wider, leathery, base contracted, not decurrent into clasping sheaths, apex acute and hooked. Inflorescence subterminal, ascending or slightly pendulous, to 20 cm, laxly many flowered; peduncle and rachis stout, basal sheaths 4 or 5; floral bracts ovate-lanceolate, 2-3 mm, membranous, apex acute. Pedicel and ovary to 5 cm. Flowers slightly fragrant, thickly textured, golden yellow, lip deeper golden yellow with red stripes on each side at base, anther cap pale yellow. Dorsal sepal oblong, 12-20 mm, 5-9 mm wide at middle, 7-veined, slightly obtuse; lateral sepals nearly equal to dorsal sepal; mentum subglobose, ca. 4 mm wide. Petals oblanceolate, ca. as long as dorsal sepal, ca. 2 × as wide as sepals, ca. 10-veined, margin minutely dentate, apex rounded; lip nearly reniform-orbicular, ca. 20 × 23 mm, adaxially densely pubescent, margin undulate, apex shallowly bilobed; disk often V-shaped, raised, sometimes with U-shaped chestnut spots. Column ca. 5 mm; anther cap tower-shaped.
Epiphytic on tree trunks in sunny evergreen broad-leaved forests, lithophytic on rocks in open forests; 500-1600 m. S and W Yunnan [NE India, Laos, Myanmar, Thailand, Vietnam].