单葶草石斛 dan ting cao shi hu

Callista porphyrochila (Lindley) Kuntze; Dendrobium caespitosum King & Pantling.

Stems erect, cylindric or narrowly fusiform, 1.5-4 cm, 2-4 mm in diam., fleshy, base slightly contracted, becoming narrowed toward apex above middle, with several internodes, current ones enclosed in leaf sheaths. Leaves 3 or 4, distichous, alternate, narrowly oblong, to 4.5 × 0.6-1(or more) cm, papery, base contracted and enlarged into sheaths, apex acute and unequally bilobed; leaf sheath gibbous, herbaceous. Inflorescences solitary, proteranthous, apparently terminal, nodding, much taller than leaves, to 8 cm, with several to more than 10 small flowers; floral bracts narrowly lanceolate, ca. 9 × 1 mm, ca. as long as or longer than pedicel and ovary, apex acuminate. Pedicel and ovary hairlike, ca. 8 mm. Flowers scented, not resupinate, spreading, thin, golden yellow, or sepals and petals pale green with red veins, lip deep purplish brown, margin pale green, column white tinged with purple. Dorsal sepal narrowly ovate-lanceolate, 8-9 mm, 1.8-2 mm wide at base, 3-veined, caudate-acuminate; lateral sepals narrowly lanceolate, ca. as long as dorsal sepal and slightly broader, 3-veined, base oblique, apex acuminate; mentum subglobose, small. Petals narrowly elliptic, 6.5-7 × ca. 1.8 mm, apex acute; lip subrhombic or elliptic, concave, ca. 5 × 2 mm, entire, subacute; disk with 3 ± thickened central longitudinal ridges. Column ca. 1 mm, base dilated, foot ca. 1.4 mm; anther cap subglobose, glabrous.

Epiphytic on tree trunks in mountain forests, lithophytic on rocks in forests; ca. 2700 m. N Guangdong (Liannan), W Yunnan (Tengchong) [Bhutan, NE India, Myanmar, Nepal, N Thailand, N Vietnam].