Herbs, perennial, achlorophyllous, holomycotrophic, rhizomatous or tuberous. Stem unbranched. Leaves alternate, amplexicaul, small. Flowers solitary, terminal, bisexual or unisexual, epigynous. Perianth of 6 tepals in 2 whorls, zygomorphic; posterior tepal large, broad, sometimes with basal callus; other tepals linear-filiform. Stamens 6; filaments short; anthers dorsifixed, dehiscence extrorse; pollen (not known from Corsiopsis) 1-aperturate. Gynoecium syncarpous, 3-carpellate; ovary unilocular with 3 parietal placentae; ovules numerous, anatropous, bitegmic, tenuinucellate; style absent or short; stigmas 3. Fruit (not known from Corsiopsis) capsular, with 3 valves. Seeds (not known from Corsiopsis) numerous, very small, winged; embryo rudimentary at time of release.