Cordyceps

Cordyceps /ˈkɔːrdəsɛps/ is a genus of ascomycete fungi (sac fungi) that includes about 400 species. All Cordyceps species are endoparasitoids, parasitic mainly on insects and other arthropods (they are thus entomopathogenic fungi); a few are parasitic on other fungi. Until recently, the best known species of the genus was Cordyceps sinensis, first recorded as yartsa gunbu in Nyamnyi Dorje's 15th century Tibetan text An ocean of Aphrodisiacal Qualities. In 2007, nuclear DNA sampling revealed this species to be unrelated to most of the rest of the genus' members; as a result it was renamed Ophiocordyceps sinensis and placed in a new family, the Ophiocordycipitaceae.

The generic name Cordyceps is derived from the Greek word kordyle, meaning "club", and the Latin stem -ceps, meaning "head". Several species of Cordyceps are considered to be medicinal mushrooms in classical Asian pharmacologies, such as that of traditional Chinese and Tibetan medicines.

When a Cordyceps fungus attacks a host, the mycelium invades and eventually replaces the host tissue, while the elongated fruit body (ascocarp) may be cylindrical, branched, or of complex shape. The ascocarp bears many small, flask-shaped perithecia containing asci. These, in turn, contain thread-like ascospores, which usually break into fragments and are presumably infective. Some current and former Cordyceps species are able to affect the behavior of their insect host: Ophiocordyceps unilateralis (formerly Cordyceps unilateralis) causes ants to climb a plant and attach there before they die. This ensures the parasite's environment is at an optimal temperature and humidity, and that maximal distribution of the spores from the fruit body that sprouts out of the dead insect is achieved. Marks have been found on fossilised leaves that suggest this ability to modify the host's behavior evolved more than 48 million years ago.