What is "claviceps purpurea"

Sclerotium \Scle*ro"ti*um\, n.; pl. Sclerotia. [NL., fr. Gr. sklhro`s hard.]

1. (Bot.) A hardened body formed by certain fungi, as by the Claviceps purpurea, which produces ergot.

2. (Zo["o]l.) The mature or resting stage of a plasmodium.

Ergot \Er"got\, n. [F. ergot, argot, lit., a spur.]

1. A diseased condition of rye and other cereals, in which the grains become black, and often spur-shaped. It is caused by a parasitic fungus, Claviceps purpurea.

2. The mycelium or spawn of this fungus infecting grains of rye and wheat. It is a powerful remedial agent, and also a dangerous poison, and is used as a means of hastening childbirth, and to arrest bleeding.

3. (Far.) A stub, like soft horn, about the size of a chestnut, situated behind and below the pastern joint.

4. (Anat.) See 2d Calcar, 3 (b) .

Claviceps purpurea is an ergot fungus that grows on the ears of rye and related cereal and forage plants. Consumption of grains or seeds contaminated with the survival structure of this fungus, the ergot sclerotium, can cause ergotism in humans and other mammals. 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.