Cyttaria darwinii is an ascomycete fungus that is parasitic on southern beech trees (Nothofagus spp.). It is restricted to the Tierra del Fuego region of southern Argentina and Chile. Charles Darwin collected the first specimens in 1832, during the voyage of the Beagle. The visible fungus grows as several to many rotund bodies of a bright tawny or orangey color and knobby surface; in addition the growth is often accompanied by swelling of the host branch or trunk. While the six Cyttaria species are generally considered parasitic, the precise nature of the parasitism and potential damage is not known. Darwin noted that this fungus formed part of the diet of local Indians, and even today it is called "Indian bread" (pan del Indio).
