137. Thelasis Blume, Bijdr. 385. 1825.
矮柱兰属 ai zhu lan shu
Authors: Xinqi Chen & Jeffrey J. Wood
Herbs, epiphytic, rather small. Stems either pseudobulbous, 1- or 2-leaved, with sheaths and sometimes additional smaller leaves at base, or short and not thickened with several leaves in 2 close opposite ranks, laterally compressed and overlapping at base. Leaves narrow, rather thin, sometimes articulate at base. Inflorescence lateral, scape arising from base of pseudobulb or node of short stem, usually slender, many flowered. Flowers resupinate, greenish yellow or white, very small, not opening widely. Sepals similar, sometimes connivent; lateral sepals concave, often carinate abaxially. Petals slightly smaller than sepals; lip sessile on base of column, entire, usually broadest and concave at base, narrowed at apex. Column short, without a foot; anther erect; pollinia 8, in 2 groups of 4, waxy, on a slender caudicle attached to a nearly narrowly elliptic viscidium; rostellum terminal, erect, 2-lobed, acuminate; stigma large.
About 20 species: from India eastward to New Guinea and the Pacific islands; two species in China.