Terrestrial glabrous herbs, arising from oval or spherical tubers. Leaf solitary, terete, more or less hollow, sheathing flowering stem for at least half its length. Flowers green to yellowish, few-many on short pedicels, spirally or alternately arranged, each subtended by a small, acute bract, column uppermost; perianth segments less than 5 mm long; dorsal sepal broad, hooded, erect; lateral sepals similar in length to dorsal sepal, but much narrower, spreading or recurved; petals shorter than or similar in length to sepals, more or less erect, incurved or spreading. Labellum sessile, about as long as other perianth segments, oblong to ovate or circular, truncate or notched, more or less pendulous or decurved against ovary; calli, if present, paired at base, and single along middle of lamina or near tip. Column short, semicylindric, with membranous, obtuse, auricle-like wings.
About 20 species in Australia, 2 extending into other Pacific countries, 6 occurring in Victoria.
Most species are self-pollinated if not visited by insects, and some are possibly apomictic.