Mycena polygramma
Description
Mycena polygramma 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. It 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.
This mushroom contains two uncommon hydroxy fatty acids and is also a bioluminescent fungus whose intensity of light emission follows a diurnal pattern.
Common names: Grooved Bonnet.
Mushroom Identification
Cap
2 to 3.5cm across; conical, becoming bell-shaped and eventually umbonate; smooth with striations almost to center; margin scalloped or sharply toothed; various tones of gray or grayish brown, becoming darker brown towards center.
Gills
Adnate; white turning pinkish-gray when fully mature.
Stem
5 to 10cm long and 0.2 to 0.4cm in diameter; white at the apex, progressively darker red-brown towards the downy base; longitudinally grooved, often very obviously but sometimes only faintly; no ring.
Spores
Ellipsoidal, 7.5-10 x 5-7μm; amyloid.
Spore Print
White.
Odor and Taste
Not distinctive.
Habitat & Ecological Role
Saprobic, nearly always on dead hardwood stumps or on rotting trunks and large branches; only very occasionally on rotting conifers.
Similar Species
Tall and slender forms of Mycena polygramma somewhat resemble M. pullata or M. praelonga. The former species is distinguished by its color, and the latter by its relationship to M. alcalina and its habitat on sphagnum.
History
The basionym of this species was defined when, in 1789, Jean Baptiste Francois (Pierre) Bulliard described this species and gave it the name Agaricus polygrammus.
The currently accepted scientific name of the Grooved Bonnet dates from 1821, when British mycologist Samuel Frederick Gray (1766 - 1828) transferred this woodland mushroom to the genus Mycena, thus making its scientific name Mycena polygramma .
Synonyms of Mycena polygramma include Agaricus polygrammus Bull., Agaricus chloroticus Jungh, Mycena polygramma f. candida J. E. Lange, and Mycena polygramma f. pumila J. E. Lange.
The specific epithet polygramma comes from Latin words poly meaning many and gramma meaning a sign, mark, or line. It is a reference to the many grooves or lines running down the stems of these woodland mushrooms.
Mycena polygramma Chemistry & Bioluminescence
Mycena polygramma contains the unusual hydroxy fatty acids 7-hydroxy-8,14-dimethyl-9-hexadecenoic acid (0.05% of the total fatty acids) and 7-hydroxy-8,16-dimethyl-9-octadecenoic acid (0.01%).
This mushroom is one of several dozen Mycena species that are bioluminescent. Unlike most luminescent organisms, M. polygramma has a diurnal rhythm of luminescence intensity, and has risen and falls of light intensity as high as 35 percent. However, this light emission is not typically noticed, as it can not be detected visually by the dark-adapted eye; sensitive photomultipliers or long exposure times are required to measure the phenomenon. The wavelength of spectral emissions from the fungus grown in pure culture is in the range 470–640 mμ.
Photo sources:
Photo 1 - Author: Arne Aronsen, Naturhistorisk museum, Universitetet i Oslo (CC BY-SA 3.0)
Photo 2 - Author: Jerzy Opioła (CC BY-SA 2.5)
Photo 3 - Author: Jerzy Opioła (CC BY-SA 2.5)
