Clovers, also called trefoils, are plants of the genus Trifolium (from Latin tres 'three' and folium 'leaf'), consisting of about 300 species of flowering plants in the legume family Fabaceae originating in Europe. The genus has a cosmopolitan distribution with the highest diversity in the temperate Northern Hemisphere, but many species also occur in South America and Africa, including at high altitudes on mountains in the tropics.
They are small annual, biennial, or short-lived perennial herbaceous plants, typically growing up to 30Â cm (12Â in) tall. The leaves are trifoliate (rarely, they have more or fewer than three leaflets; the more (or fewer) leaflets the leaf has, the rarer it is; see four-leaf clover), with stipules adnate to the leaf-stalk, and heads or dense spikes of small red, purple, white, or yellow flowers; the small, few-seeded pods are enclosed in the calyx. Other closely related genera often called clovers include Melilotus (sweet clover) and Medicago (alfalfa or Calvary clover).