Thelasis Blume, Bijdr. (1825) 385
- Genus Euproboscis Griff., Calcutta J. Nat. Hist. 5 (1845) 371
- Genus Oxyanthera Brongn. in Duperrey, Voy. Coq. Bot. (1829) 197
- Genus Rhynchophreatia Schltr., Bot. Jahrb. Syst. 56 (1921) 488
Sympodial epiphytes with very short to rather long rhizomes. Pseudobulbs present or not, consisting of one to several internodes, 1- to few-leaved; when pseudobulbs absent stem short, few- to many-leaved, with the leaves arranged in two rows. Leaves sheathing or not, glabrous, deciduous, duplicate, leathery. Inflorescence arising from the base of the pseudobulb, or lateral from the stem, a many-flowered raceme. Flowers fleshy, very small, resupinate, often hardly opening, white or green, soon becoming yellowish. Sepals free or connate at the base. Petals free, usually about as long as the dorsal sepal but mostly dissimilar to it. Lip without spur, not mobile. Column-foot absent or very short. Pollinia 8, solid, caudicles present, stipe absent, viscidium present.