Rhizomatous perennial herbs. Roots fibrous. Aerial stems and leaves annual; leaves numerous, cauline, resupinate. Inflorescence a scapose, corymbose cyme with leafy bracts. Flowers bisexual, zygomorphic; perianth segments free; sepals equal; upper pair of petals similar, lower petal differing; stamens 6, inserted on disc, filaments filiform, anthers basifixed, dehiscing introrsely by slits; ovary inferior, 3-locular; ovules several per locule; style filiform, stigma trifid. Fruit a loculicidal capsule; seeds sub-globose, rugose-tuberculate, yellow to brown.
About 50 species, from South America; 2 naturalised in Australia, 2 in Victoria.