Ergot

Ergot (pron. /ɜːrɡət/ UR-gut) 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:

Ergot (horse anatomy)

The ergot is a small callosity on the underside of the fetlock of a horse or other equine. Some equines have them on all four fetlocks; others have few or no detectable ergots. In horses, the ergot varies from very small to the size of a pea or bean, larger ergots occurring in horses with "feather" – long hairs on the lower legs. In some other equines, the ergot can be as much as 3.8 cm (1.5 in) in diameter.

Ergot comes from the French word for rooster's spur.

Evolution

Like the chestnut, the ergot is thought to be a vestige of some part of the ancestral foot of the multi-toed Equidae, the ergot corresponding to the sole pad of other extant members of Perissodactyla, such as the tapir and rhinoceros. Unlike the chestnut, which in the same individual may be large on the forelegs and smaller or even absent on the hindlegs, according to Ridgeway, the ergot is of roughly equal size on all four legs. However, as stated above, it is often noted that the ergot can be absent on some or all legs.