The restoids -- known as restios -- comprise all 310 species in the Restionaceae, a family closely related to the grasses. Large genera in the Restionaceae include Elegia, Ischyrolepis, Restio and Thamnochortus. Restoids comprise the growth form, which uniquely characterises fynbos. All members of the restoids have separate male and female plants. The seeds of many of the plants are dispersed by ants.

Restios are an integral component of the fynbos biome. In fact some contend that as restios occur together with either ericas or proteas which in turn are confined to specific zones, restios are the most important component of fynbos.

South Africa has about 69% of the world's species. Most of these are confined to the fynbos region of the Western Cape.