White clover (
Trifolium repense) is a glabrous perennial with trifoliate leaves which is widely distributed in moist temperate zones, Mediterranean areas and some cool subtropical parts of the world. It was originally introduced from the Mediterranean. During the long daylengths and high temperatures of summer, the axillary buds on the stolons produce inflorescences rather than vegetative stolon branches. Most leaves have white "V" mark, and are shiny on the underside, with white flowers. It is accompanied by white florets at the end of long peduncles that are often tinged pink, becoming deflexed with age.
Toxic components
White clover contains cyanogenic glycosides. In young leaves, the cyanogen levels may reach 350 mg of HCN per 100 g of tissue. Cyanogenesis is controlled by two independently inherited genes in white clover. Only plants possessing at least one dominant functional allele of both genes liberate HCN when damaged. Some cultivars are capable of liberating HCN and others are not. White clover can also occasionally become infested with the mold
Rhizoctonia leguminicola, which appears as a rust color seen on the top side of the clover leaf. This mold produces slaframine, which is an indolizidine alkaloidal mycotoxin that causes a condition known as
slobbers in horses that ingestion it. It appears in pastures during periods of hot and humid weather.
