Small terrestrial herbs without normal roots. Stems decumbent below and rhizome-like, ascending or erect and leafy above; rhizomes often moniliform, with many constricted nodes, internodes with 2 to several rows of root-ridges, longitudinally grooved between root-ridges, ridges densely covered with long hairs; erect stems short or long, sometimes slightly swollen at internodes. Leaves few to many, congested near base of stem or more evenly cauline, ovate, membranaceous, 5-nerved, petioles sheathed at base. Inflorescence terminal, pedunculate or rarely sessile, racemose. Flowers few to many, small, resupinate; sepals membranaceous, connate for more than half their length forming a tube; petals free, falcate, appressed to sepal tube; lip often tripartite and joined with column at base, rarely undivided and attached to base of column, hypochile saccate, bearing 2 or 2 rows of papillae on lateral side, mesochile clawed, epichile protruding beyond sepal tube, dilated and bilobed, lobes dentate or pectinate at margins; column erect, with 2 appendages on ventral side, appendages (stylids) subequal in length and parallel to rostellum, rarely reflexed or low and flange-like; anther terminal on dorsal side of column, erect, 2-celled; pollinia 2, sectile, clavate or cylindrical, with a slender stalk attached to a tegula stipe, stipe as long as or longer than pollinia; stigma 2, on lateral sides of column , near base of restellum; rostellum erect, triangular, deeply cleft into long arms, with long or short viscidium on ventral side.
About 22 species, distributed in tropical Africa and Asia, extending from Pacific islands to Australia and Papua New Guinea. Seven species in Taiwan.