Cordyceps

Cordyceps is a genus of ascomycete fungi (sac fungi) that includes about 600 species. Most "Cordyceps" species are endoparasitoids, parasitic mainly on insects and other arthropods (they are thus entomopathogenic fungi); a few are parasitic on other fungi. The generic name "Cordyceps" is derived from the Greek word κορδύλη "kordýlē", meaning "club", and the Greek word κεφαλή "cephali", meaning "head".
The genus has a worldwide distribution and most of the approximately 600 species that have been described are from Asia (notably Nepal, China, Japan, Bhutan, Korea, Vietnam, and Thailand). "Cordyceps" species are particularly abundant and diverse in humid temperate and tropical forests.
Subtaxa.
There are two recognized subgenera:
"Cordyceps" subgen. "Epichloe" was at one time a subgenus, but is now regarded as a separate genus, "Epichloë".
"C. sinensis" was shown in 2007 by nuclear DNA sampling to be unrelated to most of the rest of the members of the genus; as a result it was renamed "Ophiocordyceps sinensis" and placed in a new family, the Ophiocordycipitaceae, as was "Cordyceps unilateralis". Other species previously included in the genus "Cordyceps" have now been placed in the genus "Tolypocladium".
"Cordyceps" and "Metacordyceps" spp. are now thought to be the teleomorphs of a number of anamorphic, entomopathogenic fungus "genera" such as: "Beauveria" ("Cordyceps bassiana"), "Lecanicillium, Metarhizium" and "Nomuraea".
Biology.
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.
Research.
Polysaccharide components and cordycepin are under basic research and have been isolated from "C. militaris".
Sources and uses.
Cordyceps are used in traditional Chinese medicine, but there is no scientific evidence that their use has any clinical effect on human diseases.
Fiction.
Cordyceps is depicted in the 2013 video game, The Last of Us, in which a mutated form of the fungus that infects humans creates a widespread pandemic that eventually causes the collapse of civilization. In the game, the Cordyceps fungus that creates zombie-like symptoms in insects kills 60% of the human population over the course of 20 years and leaving the remaining human population to fight for survival.