Portal:Fungi/Selected article/13

Geastrum triplex, commonly known as the collared earthstar, the saucered earthstar, or the triple earthstar, is an inedible species of fungus belonging to the genus Geastrum, or earthstar fungi. First described in 1840 as Geaster triplex, several authors have suggested that Geastrum indicum, described in 1832, is the legitimate name for the species. Immature fruit bodies are spherical—somewhat resembling puffballs with pointed beaks—and are partially or completely buried in the ground. As the fungus matures, the outer layer of tissue (the exoperidium) splits into four to eight pointed segments which spread outwards and downwards, lifting and exposing the spherical inner spore sac. The spore sac contains gleba, a mass of spores and fertile mycelial tissue that when young is white and firm, but ages to becomes brown and powdery. Often, a layer of the exoperidium splits around the perimeter of the spore sac so that it appears to rest in a collar or saucer. Atop the spore sac is a small pointed beak, the peristome, which has a small hole from which spores may be released. The species is the largest of the earthstar fungi, with a tip to tip length of an expanded mature specimen reaching up to 12 centimeters (4.7 in).

Geastrum triplex is a common and widespread species found in the detritus and leaf litter of hardwood forests in many parts of the world, including Asia, Australasia, Europe, and both North and South America. Fruit bodies have been analyzed chemically to determine their lipid content, and various chemical derivatives of the fungal sterol ergosterol have been identified. The fungus has a history of use in the traditional medicines of native North America and China.