Herbs, terrestrial, slender. Tubers spreading horizontally, slender, fleshy. Stem erect, terete, glabrous, with (1 or)2 or 3 basal leaves. Leaves ovate-oblong to oblong-elliptic, base attenuate into short petiole-like sheath. Inflorescence terminal, racemose, with a few secund flowers; floral bracts nearly as long as ovary. Flowers resupinate, small; ovary twisted, cylindric-fusiform, glabrous; sepals and petals free, spreading, subequal in size; lip spreading, 3-lobed near middle, base adnate to column, spurred; spur shorter than ovary; anther erect, sessile, oblong, apex aristate, 2-locular; locules parallel, not protruding at base; pollinia 2, granular-farinaceous, sectile; caudicles very short, attached to a common viscidium; viscidium narrowly oblong-elliptic, enclosed in a chamber formed by lip and column; rostellum flattened, elongate, canaliculate, beaklike, slightly exceeding anther, 1-toothed on either side at middle, basal half entirely united with column; stigma lobes 2, separate, linear; lateral appendages 2, elongate, positioned on either side of anther base, exceeding anther.

A genus distinguished by its long, bidentate rostellum and 2-lobed stigma, its placement remains a matter of contention. The nature of the column has been thought to affiliate the genus with Gymnadenia and Neottianthe (Bull. Fan Mem. Inst. Biol. Bot. 7: 133. 1936); however, Tsaiorchis has also been considered congeneric with Diphylax (Pridgeon et al., Gen. Orchid. 2: 284-286. 2001).

● One species: China.

(Authors: Chen Xinqi (陈心启 Chen Sing-chi); Stephan W. Gale, Phillip J. Cribb)