Herbaceous or shrubby perennials. Leaves alternate or opposite, often succulent. Flowers bisexual, dioecious, or bisexual and unisexual flowers on same plant, sessile, axillary, solitary or paired. Perianth tube flat to cup-shaped, expanding in fruit; perianth lobes 5 equal, but perianth usually with a single deep slit (radicular slit) opposite radicle between 2 lobes and sometimes extending down tube; stamens 5; stigmas 2 or 3. Fruiting perianth spongy, leathery, crustaceous or woody, often developing a spreading papery wing which is entire, once-slit radially, or 5-lobed, sometimes with accessory vertical lobes or appendages. Fruit a utricle; pericarp membranous to crustaceous; style sometimes enlarging to a hemispherical or conical protuberance.
Endemic Australian genus of 58 species, mostly in arid or semi-arid temperate zones.