number of genera by various authors, resulting in several synonyms: Agaricus flabelliformis (Johann Friedrich Gmelin, 1792), Pocillaria stiptica (Otto Kuntze, 1898), Rhipidium stipticum (Karl Friedrich Wilhelm Wallroth, 1833), Crepidopus stipticus (Samuel Frederick Gray, 1821), Pleurotus stipticus (Paul Kummer), Lentinus stipticus (Joseph Schröter, 1885), and Merulius stipticus (Jean-Baptiste Lamarck). It was Finnish mycologist Petter Karsten who in 1879 assigned its current name. Panellus stypticus is still used in the literature as a variant spelling. Panellus stipticus is the type species of the genus Panellus, and, in Rolf Singer's authoritative 1986 classification of the Agaricales, it is also the type species of subgenus Panellus, an infrageneric (below the taxonomic level of genus) grouping of Panellus species characterized by the absence of cystidia on the sides of the gills. More recently, phylogenetic analyses of the sequences of their ribosomal large subunit genes have concluded that Panellus stipticus is closely related to the poroid mushroom Dictyopanus pusillus. The molecular analysis supports a previous assessment by mycologists Harold Bursdall and Orson K. Miller, who in 1975 suggested merging Dictyopanus into Panellus based on similarities in spore shape, stem structure, and the ability of dried fruit bodies to revive when moistened. Formerly grouped in the family Tricholomataceae, a wastebasket taxon of gilled mushrooms with white spores, P. stipticus is now classified in the Mycenaceae, after a large-scale phylogenetic analysis revealed "a previously unsuspected relationship between Mycena and Panellus (including Dictyopanus)". The fungus is commonly known as the bitter oyster, the luminescent panellus, the astringent panus, or the styptic fungus. The specific epithet stipticus refers to its purported value in stopping bleeding. Etymologically, it is a Greek equivalent to the Latin word astringens, deriving from στυπτικός (styptikós), itself from the verb στύφειν (styphein), "to contract". Description The fungus normally exists unseen, in the form of a mass of threadlike vegetative cells called a mycelium, inhabiting rotting wood; only when suitable environmental conditions of temperature, moisture, and nutrient availability are achieved does the fungus produce the reproductive structures known as fruit bodies, or mushrooms. The cap of the fruit body is kidney- or clamshell-shaped, convex to roughly flat, with dimensions of by . The edges of the caps are scalloped with small rounded teeth, and curved slightly inward. The cap surface is dry, with a pattern of block-like areas similar to cracked dried mud; the surface is also covered with small fine hairs that give it a somewhat