The dark hard-walled mass of hyphae produced by the fungus Claviceps purpurea (see ascomycota) in the grain of the cereals and other grasses that it parasitizes. Ergots are the sclerotia of this species—resting bodies that germinate in favourable conditions to produce mycelia or ascocarps. They contain alkaloids related to LSD, which cause blood vessels to constrict and are used therapeutically in the treatment of migraine and haemorrhage. Ingestion of infected grain can result in ergot poisoning (ergotism), with symptoms of gangrene and hallucinations—known as ‘St Anthony’s fire’ in the Middle Ages.