Mycena Aurantiomarginata

''Mycena aurantiomarginata'', commonly known as the golden-edge bonnet, is a species of agaric fungus in the family Mycenaceae. First formally described in 1803, it was given its current name in 1872. Widely distributed, it is common in Europe and North America, and has also been collected in North Africa, Central America, and Japan. The fungus is saprobic, and produces fruit bodies (mushrooms) that grow on the floor of coniferous forests. The mushrooms have a bell-shaped to conical cap up to in diameter, set atop a slender stipe up to long with yellow to orange hairs at the base. The fungus is named after its characteristic bright orange gill edges. A microscopic characteristic is the club-shaped cystidia that are covered with numerous spiky projections, resembling a mace. The edibility of the mushroom has not been determined. ''M. aurantiomarginata'' can be distinguished from similar ''Mycena'' species by differences in size, color, and substrate. A 2010 publication reported the discovery and characterization of a novel pigment named mycenaaurin A, isolated from the mushroom. The pigment is responsible for its color, and it has antibiotic activity that may function to prevent certain bacteria from growing on the mushroom.

Taxonomy

The species, originally named ''Agaricus marginatus'' by the Danish naturalist Heinrich Christian Friedrich Schumacher in 1803, has several synonyms. Elias Magnus Fries renamed it ''Agaricus aurantio-marginatus'' in his 1821 ''Systema Mycologicum'', while Christiaan Hendrik Persoon called it ''Agaricus schumacheri'' in 1828. Although Schumacher had the earliest publication date, Fries's name is sanctioned, and so the specific epithet he used is given nomenclatural precedence. French mycologist Lucien Quélet transferred the species to the genus ''Mycena'' in 1872. In 1930 Karel Cejp considered it to be a variety of '' Mycena elegans''.

According to Alexander H. Smith's organization of the genus ''Mycena'', ''M. aurantiomarginata'' is classified in section ''Calodontes'', subsection ''Granulatae'', which contains species with roughened cheilocystidia ( cystidia on gill edges), such as '' M. rosella'', '' M. flavescens'', ''M. elegans'', and '' M. strobilinoides''. In his 1992 study of ''Mycena'', Dutch mycologist Rudolph Arnold Maas Geesteranus put ''M. aurantiomarginata'' in the section ''Luculentae'', characterized by species with an olive to yellowish-olive and moist cap, pallid to gray-olive gills with bright orange margins, brownish to grayish-olive stipes, white spore deposit, and spiny cystidia.'' M. aurantiomarginata'' was included in a 2010 molecular analysis focused on clarifying the phylogenetic relationships between Northern European species in the section ''Calodontes''. The results suggested that, based on the similarity of nuclear large subunit ribosomal DNA sequences, the fungus is closely related to '' M. crocata'' and '' M. leaiana''. This conclusion was previously corroborated by research that used molecular analysis to demonstrate that several ''Mycena'' species can be mycorrhizal partners of the orchid ''Gastrodia confusa''.

The specific epithet ''aurantiomarginata'' is Latin, and refers to the orange edges of its gills (''aurantius'', "orange"; ''marginata'', "bordered"). In the United Kingdom, the mushroom is commonly known as the "golden-edge bonnet".

Description

The cap of ''M. aurantiomarginata'' ranges in shape from obtusely conic to bell-shaped, and becomes flat in maturity, reaching diameters of . The cap color is variable, ranging from dark olive fuscous