草石斛 cao shi hu

Dendrobium wilmsianum Schlechter.

Stems cylindric, ± fusiform, 1.5-3 cm, 4-5 mm in diam., fleshy, with 3-6 nodes, current ones enclosed in leaf sheaths, previous year’s naked stems golden yellow. Leaves 2-5, distichous, alternate, lowermost smaller than upper, oblong, 1-2.5 × 0.4-0.6 cm or more, herbaceous, base dilated into sheaths, apex obtuse and unequally bilobed; leaf sheaths obliquely drum-shaped, papery, loosely clasping; sheath mouth obliquely truncate. Inflorescences 1-5, subterminal or lateral on upper part of current year’s stem, erect, usually 1-2 cm, not exceeding leaves, 3-6-flowered; floral bracts ovate-lanceolate, 2-3 × ca. 1 mm, 1-veined, acute. Pedicel and ovary ca. 4 mm. Flowers spreading, white, lip pale green. Dorsal sepal ovate-oblong, ca. 4 × 1.8 mm, 3-veined, acute; lateral sepals obliquely triangular-lanceolate, ca. 4 × to 3.5 mm, 3- or 4-veined, base oblique, apex acute; mentum conic. Petals suborbicular, ca. 4 × 1.7 mm margin slightly undulate, apex acute; lip suborbicular, ca. 5 × 4 mm, inconspicuously 3-lobed; lateral lobes subrounded, margin finely toothed above middle; mid-lobe broadly ovate-triangular, margin cristate-corrugate, apex mucronate; disk with fleshy ridges combined by 2 or 3 lamellae, apex slightly narrowed. Column ca. 2 mm, upper part enlarged; anther cap broadly conic, front margin slightly notched. Capsule ovoid, ca. 5 mm in diam., with 3 ribs.

Epiphytic on tree trunks in broad-leaved forests; 1600-1900 m. S Yunnan [Myanmar, N Thailand].