Bijdr. (1825) 304
Sympodial epiphytes with tufted habit, or less often with pendulous elongated rhizomes. Pseudobulbs consisting of one internode, very slender, resembling a petiole, or almost absent, 1- or rarely 2-leaved at the apex. Leaves not sheathing at the base, glabrous, dorso-ventrally flattened or terete, deciduous, duplicate, leathery. Inflorescence terminal, usually very short, carrying a single flower, often occurring in clusters. Flowers small to very small, resupinate or not. Lateral sepals connate, forming a mentum that often resembles a spur. Petals usually narrower than the sepals. Lip without spur, not mobile. Column at the apex with two lobes. Column-foot present. Pollinia 8, solid, caudicles absent, stipe absent, viscidium present.
India, tropical East Asia, Malaysia, Indonesia, the Philippines, Papua New Guinea, Pacific islands, east to Vanuatu (not in Australia). About 80 species; in New Guinea c. 50 species.
Epiphytes in lowland and montane forest, often in shady positions.
With very few exceptions the members of this genus are inconspicuous, often rush-like plants with tiny, dull-coloured flowers produced just below the base of the leaves. The New Guinea species are badly in need of revision. Most species of Ceratostylis are easily cultivated.
Two sections are usually distinguished: sect. Ceratostylis consisting of species with a tufted habit with the stems generally at least as long as the leaves and often longer, and sect. Pleuranthemum consisting of species with or without elongated rhizomes and with the stems much shorter than the leaves. In New Guinea almost all species belong to sect. Ceratostylis, with only one or two species in sect. Pleuranthemum.