Dendrobium chrysotoxum Lindley
- genus Dendrobium Sw.
Stem pseudobulbous, erect, fusiform, 6-30 cm, 1.5-5 cm in diameter at middle, with 2-5 internodes, with many bluntly rounded ridges, golden-yellow when dry. Leaves 2-5, subterminal, oblong, to 19 cm long, 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 long, 5-9 mm wide at middle, 7-veined, slightly obtuse; lateral sepals nearly equal to dorsal sepal; mentum semiglobose, ca. 4 mm wide. Petals oblanceolate, ca. as long as dorsal sepal, ca. 2 times 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 opposite V-shaped raised, sometimes with U-shaped chestnut spots. Column ca. 5 mm; anther cap tower-shaped.
Dendrobium chrysotoxum is close relative of Dendrobium sulcatum, but differs from the latter in its stems not laterally compressed, thickly fusiform, with many ridges (vs. distinctly laterally compressed, clavate), petal margin minutely dentate (vs. entire), lip margin undulate (vs. minutely erose to ciliate-hairy).
The chromosomal number of Dendrobium chrysotoxum is 2n = 38 (Cheng et al., 1985; Hashimoto, 1987; Vijayakumar and Subramanian, 1994).
Ecology and Distribution
Flowering from March to May.
Dendrobium chrysotoxum is occurring in S and W Yunnan of China, NE India, Laos, Myanmar, Thailand, and Vietnam.
Epiphytic on tree trunks in sunny evergreen broad-leaved forests, lithophytic on rocks in open forests; 500-1600 m.
- Callista chrysotoxa (Lindley) Kuntze (synonym)
- Dendrobium chrysotoxum var. delacourii Gagnepain (synonym)