Mycena Polygramma

''Mycena polygramma'', commonly known as the grooved bonnet, is a species of mushroom in the family Mycenaceae. The inedible fruit bodies are small, pale gray-brown mushrooms with broadly conical caps, pinkish gills. They are found in small troops on stumps and branches of deciduous and occasionally coniferous trees. The mushroom is found in Asia, Europe, and North America, where it is typically found on twigs or buried wood, carrying out its role in the forest ecosystem by decomposing organic matter, recycling nutrients, and forming humus in the soil. ''M. polygramma'' contains two uncommon hydroxy fatty acids and is also a bioluminescent fungus whose intensity of light emission follows a diurnal pattern.

Taxonomy

First called ''Agaricus polygrammus'' by French mycologist Jean Bulliard in 1789, the species was later sanctioned under that name by Elias Magnus Fries in his ''Systema Mycologicum''. It was soon after transferred into the genus ''Mycena'' in 1821 by Samuel Frederick Gray, who raised many of Fries' sub-generic divisions to the genus level. ''Agaricus chloroticus'', described by Friedrich Franz Wilhelm Junghuhn in 1830, is the only known taxonomic synonym. The specific epithet is derived from the Greek πολύς meaning "many" and γραμμή, or "line". It is commonly known as the "grooved bonnet".

Description

The cap of the ''M. polygramma'' fruit body is in diameter, and initially egg- to cone-shaped, but expands to become conic to bell-shaped or nearly convex with an abrupt small umbo, or at times plane with a conic umbo. On young fruit bodies, the cap margin is slightly curved inward, and frequently has scalloped edges; in maturity the margin flares out or is recurved and wavy. The surface of the cap is initially covered with short, fine whitish or grayish hairs that often persist until near maturity. With age, the cap surface becomes smooth, the color dark brownish gray to black beneath the bloom, fading slowly to a pale gray, and nearly pinkish-buff at times. The cap margin is opaque and frequently has narrow, deep furrows or grooves, with the surface often more or less uneven and appearing as if streaked with glistening lines. The flesh is very hard and cartilaginous, watery grayish to white, rather thin, and with no distinctive odor and a mild taste.

The gills are narrowly adnate (attached squarely to the stem) or have a short decurrent tooth, and are packed close together, with 30–38 gills reaching the stem. They are broad anteriorly (4–7 mm), white or whitish, in age flushed with pink, often with sordid-brownish stains, and with edges pallid and even. The stem is long, thick, very brittle and cartilaginous, equal, and tubular. It sometimes has a well-developed pseudorrhiza that resembles white cotton, and the base is covered with stiff white hairs, and often it stains reddish brown. The surface has fine straight or sometimes twisted longitudinal striations. The surface is ashy-gray or paler grayish brown beneath the silvery covering, at times nearly smooth, with the apex pallid and faintly powdered.
''Mycena polygramma'' is a bioluminescent mushroom, although the extent of luminescence can vary considerably. The mushroom is inedible, and has a mild to slightly acrid