trefoil

Any of several clover plants of a group belonging to the pea family, the leaves of which are divided into three leaflets. The name is also used for other plants with leaves divided into three lobes. (Genus Trifolium, family Leguminosae.)

Bird's-foot trefoil Lotus corniculatus, also belonging to the pea family, is a low-growing perennial found in grassy places throughout Europe, northern Asia, parts of Africa, and Australia. It has five leaflets to each leaf, but the first two are bent back so it appears to have only three. The yellow flowers, often tinged orange or red, are borne in heads with only a few blooms. Hop trefoil T. campestre has leaves with only three leaflets and tight-packed round heads of yellow flowers about 1.5 cm/0.6 in across. It also grows in grassy places throughout Europe, western Asia, North Africa, and North America. In Australia, Austral trefoil Lotus australis is a widespread native with pink or white flowers. It is suspected of being poisonous.