Claviceps purpurea (Fr.) Tul. Mutterkorn Ergot du seigle, ErgotMost easily recognized in the sclerotial stage, a violet-black spindle-shaped structure longitudinally furrowed, up to 1cm long, formed in the inflorescences of grasses. In the autumn, the mature sclerotium falls to the ground, over-wintering in this state until late spring, when after a period of chilling, tiny pale pinkish or purplish drumstick-shaped fruit bodies develop from it producing thread-like asco-spores, 100 x 1µ. These infect other grasses belonging to several genera including some of our most important food crops, barley, oats, rye and wheat. (Shown here on Arrhenatherum elatius [L.]) Season – sclerotia summer to early autumn, fruit bodies spring. Frequent. Deadly poisonous. Distribution, America and Europe.

Poisoning by C. purpurea (ergotism) has been recorded since the Middle Ages. Outbreaks were so sudden and inexplicable that many myths and superstitions grew up around the affliction, which was widely believed to be divine punishment on sinners. Such were the beliefs and symptoms of the disease that for centuries, it was commonly known as Holy Fire. The poisoning can take two forms: that of a burning sensation in the limbs followed by their becoming gangrenous due to the constriction of blood vessels, or affecting the mind causing hallucinations, psychotic behavior and convulsions.
The connection between ergotism and grain infected by C. purpurea was only fully realized this century. Pharmacological analysis of the sclerotia revealed a mixture of powerful chemicals, among them compounds related to LSD.
Even before the complexity of ergot’s chemistry was understood, it was widely used for centuries by midwives to stimulate contractions and so aid childbirth. The crude drug is dangerous due to its many components and their side effects, however, the purified derivatives are now used in medicine in the treatment of migraine and other disorders as well as in obstetrics.