Iridorkis Thouars (1809), not Iridorchis Blume (1859); Titania Endlicher.

Herbs, epiphytic. Stems often enclosed in leaf base, usually clustered, rarely borne on an elongate rhizome, erect or pendulous, short or somewhat elongate. Leaves iridiform and unifacial, rarely terete, often fleshy, articulate or not at base, distichous, usually equitant, often imbricate at base, often dilated near base into flattened sheaths, often with a narrow membranous margin on adaxial side in basal half. Inflorescences terminal, racemose, unbranched, pubescent or glabrous, usually many flowered; peduncle often with sterile bracts below; floral bracts persistent, often erose. Flowers often in whorls, not resupinate, flat, very small, usually only 1-2 mm in diam.; ovary glabrous or papillate. Sepals and petals free, spreading, petals often narrower than sepals, sometimes erose; lip usually spreading, sessile, entire or lobed, margin sometimes erose or fimbriate, occasionally concave at base, with or without calli, spur absent; lateral lobes often embracing column. Column erect, short, lacking a foot, wings usually absent; anther cap terminal, firmly attached to column apex, 2-locular; pollinia 4, cohering in 2 unequally sized pairs, waxy; viscidium absent or abbreviated; stigma transversely reniform to ovate; rostellum protruding.

Oberonia teres Kerr (Bull. Misc. Inform. Kew 1927: 214. 1927), formerly considered endemic to Thailand, was recorded from W Yunnan (Lushui: Gaoligong Shan, ca. 2400 m) by X. H. Jin, H. Li, and D. Z. Li (Acta Phytotax. Sin. 45: 805-806. 2007). The present authors could not confirm this because they have not seen the specimen (X. H. Jin 7029, PE).

Between 150 and 200 species: centered in tropical S and SE Asia but extending to tropical Africa, Madagascar, the Mascarene Islands, the Philippines, New Guinea, NE Australia, and the SW Pacific islands across to Tahiti; 33 species (11 endemic) in China.

(Authors: Chen Xinqi (陈心启 Chen Sing-chi); Paul Ormerod, Jeffrey J. Wood)