短棒石斛 duan bang shi hu

Callista capillipes (H. G. Reichenbach) Kuntze.

Stems nearly compressed fusiform, 8-15 cm, at middle ca. 1.5 cm in diam., fleshy, unbranched, with many obtuse longitudinal ridges and few internodes. Leaves 2-4, near apex of stem, narrowly oblong, usually 10-12 × 1-1.5 cm, leathery, base dilated into clasping sheaths, apex slightly obtuse and obliquely emarginate. Inflorescences from old leafless stems, suberect, 12-15 cm, laxly 2- to several flowered; peduncle with 2 or 3 sheaths at base, membranous; floral bracts pale white, ovate, small, ca. 5 × 3 mm, apex acute. Pedicel and ovary pale yellowish green, ca. 2 cm. Flowers spreading; sepals and petals golden yellow, lip a deeper hue, with purplish red stripes, column golden yellow. Dorsal sepal ovate-lanceolate, ca. 12 mm, ca. 5 mm wide at middle, 3-veined, apex acute; lateral sepals nearly equal in size to dorsal sepal; mentum oblong, ca. 4 mm, obtuse-rounded. Petals ovate-elliptic, ca. 15 × 9 mm, 4-veined, apex slightly obtuse; lip subensiform, ca. 20 × 25 mm, both surfaces densely pubescent, embracing column on both sides at base, margin undulate, apex emarginate. Column ca. 4 mm; anther cap ± tower-shaped, front margin subtruncate and notched; clinandrium broad, both lateral upper margins irregularly notched.

Epiphytic on tree trunks in evergreen broad-leaved forests; 900-1500 m. S Yunnan [NE India, Laos, Myanmar, Nepal, Thailand, Vietnam].

A related Indochinese species, Dendrobium braianense Gagnepain (Bull. Mus. Natl. Hist. Nat., sér. 2, 10. 436. 1938), originally described from Vietnam and treated in synonymy under D. capillipes by Seidenfaden (Opera Bot. 114: 229. 1992), is a showier, more floriferous plant. This entity reappeared in markets in Thailand in the 1990s and was treated as a distinct species by H. P. Wood (Dendrobiums, 599-600. 2006), with D. capillipes var. elegans H. G. Reichenbach and D. ejirii T. Yukawa in synonymy. H. P. Wood believes that D. braianense may not occur in China, although he included Yunnan within its distribution in his book (loc. cit.: 600). A brief description is provided here for comparison with D. capillipes: stem pseudobulbous, slightly clavate, to 17 × 1.5 cm, variably deciduous; leaf ca. 10 × 2.5 cm; inflorescences borne on last year’s leafy or leafless stems, sometimes on older stems; racemes lateral, up to 3 per stem, arching, up to 7-flowered (bloom may repeat at a different node); flowers ca. 4 cm in diam.; anther cap pointed.