Ergot () or ergot fungi refers to a group of fungi of the genus Claviceps. The most prominent member of this group is Claviceps purpurea (rye ergot fungus). This fungus grows on rye and related plants, and produces alkaloids that can cause ergotism in humans and other mammals who consume grains contaminated with its fruiting structure (called ergot sclerotium). Claviceps includes about 50 known species, mostly in the tropical regions. Economically significant species include C. purpurea (parasitic on grasses and cereals), C. fusiformis (on pearl millet, buffel grass), C. paspali (on dallis grass), C. africana (on sorghum) and C. lutea (on paspalum). C. purpurea most commonly affects outcrossing species such as rye (its most common host), as well as triticale, wheat and barley. It affects oats only rarely. C. purpurea has at least three races or varieties, which differ in their host specificity: G1 – land grasses of open meadows and fields; G2 – grasses from moist, forest and mountain habitats; G3 (C. purpurea var. spartinae) – salt marsh grasses (Spartina, Distichlis).

Closest relatives