Claviceps: A genus of ascomycetous fungi, family Clavicipitaceae, order Hypocreales, parasitic on various grasses (POACEAE). The sclerotia contain several toxic alkaloids. Claviceps purpurea on rye causes ergotism.Ergot Alkaloids: Alkaloids originally isolated from the ergot fungus Claviceps purpurea (Hypocreaceae). They include compounds that are structurally related to ergoline (ERGOLINES) and ergotamine (ERGOTAMINES). Many of the ergot alkaloids act as alpha-adrenergic antagonists.Lysergic AcidErgotamine: A vasoconstrictor found in ergot of Central Europe. It is a serotonin agonist that has been used as an oxytocic agent and in the treatment of MIGRAINE DISORDERS.Secale cereale: A hardy grain crop, rye, grown in northern climates. It is the most frequent host to ergot (CLAVICEPS), the toxic fungus. Its hybrid with TRITICUM is TRITICALE, another grain.Ergotism: Poisoning caused by ingesting ergotized grain or by the misdirected or excessive use of ergot as a medicine.Cyperus: A plant genus of the family CYPERACEAE. SESQUITERPENES are found in some of the species.Ascomycota: A phylum of fungi which have cross-walls or septa in the mycelium. The perfect state is characterized by the formation of a saclike cell (ascus) containing ascospores. Most pathogenic fungi with a known perfect state belong to this phylum.Ergolines: A series of structurally-related alkaloids that contain the ergoline backbone structure.