Any legume of the genus Trifolium, composed of 300 or more annual and perennial species, found in most temperate and subtropical regions. The alternate, compound leaves usually have three toothed leaflets. The very small, fragrant flowers are crowded into dense heads. Clovers are highly palatable to livestock and high in protein, phosphorus, and calcium, thus providing valuable nourishment in the form of hay, pasture, and silage. They also improve and conserve soil by adding nitrogen and increasing the availability of other nutrients for crops that follow. The most important agricultural species are red clover (T. pratense), white clover (T. repens), and alsike clover (T. hybridum).