Epiphytes or lithophytes, small, rather delicate, often forming dense mats. Stems tufted, erect to spreading, slender, with many nodes, completely enclosed in tubular sheaths of leaves, leafy. Leaves distichous, alternate, lying in one plane by twisting of sheathing bases, usually small, short, sheaths tubular, articulate. Inflorescences terminal, lateral, or both, rarely exceeding 2 cm, few to many flowered; floral bracts persistent. Flowers resupinate, white or green, often with purple markings, minute or small, often not opening widely. Sepals adnate at base, or free; lateral sepals broad at base and adnate to column foot forming an often spurlike mentum. Petals often slightly smaller than dorsal sepal; lip attached to end of column foot, entire or obscurely 3-lobed, narrow, with a simple or bilobed basal appendage. Column short, foot long and often curved upward; anther erect, anther cap long acuminate; pollinia 4, waxy, separate, on 1 or 2 caudicles, often narrowly obovoid, commonly attached to a solitary viscidium.

About 60 species: from India and Sri Lanka to China, south and east through Indonesia and New Guinea to the Pacific islands; two species (one endemic) in China.

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