1. Thelasis pygmaea (Griffith) Blume, Fl. Javae Nov. Ser. 1: 19. 1858.
矮柱兰 ai zhu lan
Euproboscis pygmaea Griffith, Calcutta J. Nat. Hist. 5: 372. 1844; Thelasis clausa Fukuyama; T. elongata Blume; T. hongkongensis Rolfe; T. pygmaea var. multiflora J. D. Hooker.
Pseudobulbs tufted, flattened globose, 3-10 × 7-18 mm, apex often with 1 large leaf and 1(or 2) smaller leaves. Larger leaf blade narrowly oblong-oblanceolate to nearly narrowly oblong, (2.7-)4-8(-12) × 0.6-1.3 cm, slightly fleshy, base contracted into a short, conduplicate petiole, apex obtuse, acute, or unequally bilobed; small leaf blade suboblong, 0.7-1.5 cm, sometimes absent. Inflorescence 10-20(-30) cm, slender, with 2 or 3 basal sheaths; rachis ± arching, 5-10 cm, often thickened, densely many flowered; floral bracts persistent, often slightly tinged with purplish, ovate-triangular or ovate-lanceolate, ca. 2 mm. Flowers yellowish green, not opening widely; pedicel and ovary ca. 3 mm. Dorsal sepal ovate-lanceolate or oblong-lanceolate, 2-2.5 × ca. 1 mm; lateral sepals similar to dorsal sepal, cymbiform, abaxially keeled or sometimes narrowly winged. Petals suboblong or narrowly oblong, ca. 2 × 0.7 mm; lip ovate-triangular, ca. 1.8 × 1.2 mm, margin incurved, apex acuminate. Column short. Fl. Apr-Oct. 2n = 30.
Epiphytic on tree trunks and branches or lithophytic on rocks in forests or along valleys; below 2000 m. Hainan, Hong Kong, E and S Taiwan, S and SE Yunnan [India, Indonesia, Malaysia, Myanmar, Nepal, New Guinea, Philippines, Thailand, Vietnam; Pacific islands (Solomon Islands)].