Panellus Stipticus

Panellus stipticus, commonly known as the bitter oyster, the astringent panus, the luminescent panellus, or the stiptic fungus, is a species of fungus in the Mycenaceae family, and the type species of the genus Panellus. A common and widely distributed species, it is found in North America, Europe, and Asia, where it grows in groups or dense overlapping clusters on the logs, stumps, and trunks of deciduous trees, especially beech, oak, and birch. Individual fruit bodies are fan- or kidney-shaped, orange-yellow to brownish, and attached to the decaying wood by short stubby stalks that are attached off-center or on the side of the caps. The fungus, which was given its current binomial in 1879, has been known by many names since French mycologist Jean Bulliard first described it as Agaricus stypticus in 1783.

Panellus stipticus is one of several dozen species of fungi that are bioluminescent. Strains from eastern North America are typically bioluminescent, but those from the Pacific regions of North America and other continents are not. The luminescence is localized to the edges of the gills and the junction of the gills with the stem and cap. Bioluminescence is also observable with mycelia grown in laboratory culture, and the growth conditions for optimal light production have been studied in detail. Several chemicals have been isolated and characterized that are believed to be responsible for light production. Genetic analysis has shown that luminescence is controlled by a single dominant allele. The luminescent glow of this and other fungi inspired the term foxfire coined by early settlers in eastern and southern North America.