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.

Mycena polygramma
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Mycenaceae
Genus: Mycena
M. polygramma
Binomial name
Mycena polygramma
(Bull.) Gray (1821)
  • Agaricus chloroticus Jungh.
  • Agaricus polygrammus Bull. (1789)
  • Mycena polygramma f. candida J.E.Lange (1914)
  • Mycena polygramma f. pumila J.E.Lange (1914)
Mycena polygramma
View the Mycomorphbox template that generates the following list
Gills on hymenium
Cap is conical
Hymenium is adnate
Stipe is bare
Spore print is white
Ecology is saprotrophic
Edibility is inedible



First called Agaricus polygrammus by French mycologist Jean Bulliard in 1789,[3] the species was later sanctioned under that name by Elias Magnus Fries in his Systema Mycologicum.[4] It was soon after transferred into the genus Mycena in 1821 by Samuel Frederick Gray,[5] 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.[1] The specific epithet is derived from the Greek πολύς meaning "many" and γραμμή, or "line".[6] It is commonly known as the "grooved bonnet".[7]


The gills are squarely attached to the stem and flushed with pink in maturity.

The cap of the M. polygramma fruit body is 2 to 4 cm (0.8 to 1.6 in) 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.[8]

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 6 to 15 cm (2.4 to 5.9 in) long, 0.2 to 0.5 cm (0.1 to 0.2 in) 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.[8]

Various images of M. polygramma from Bulliard's Herbier de la France, 1789

Mycena polygramma is a bioluminescent mushroom, although the extent of luminescence can vary considerably.[9] The mushroom is inedible,[10] and has a mild to slightly acrid taste and a "pleasant" odor.[11]

Microscopic features


Collected in deposit, such as in a spore print, the spores appear white. Viewed with a light microscope, the spores are broadly ellipsoid in shape, smooth, amyloid, with dimensions of 7.5–10 by 5–6 μm. Occasionally the spores contain oil droplets.[10] The basidia (pore-bearing cells) are four-spored, 26–30 by 7–8 μm. The cheilocystidia are scattered to abundant, aciculate or with the midportion somewhat enlarged and the apex forked or branched and give rise to two or several contorted finger-like projections. Pleurocystidia are not differentiated.[8]

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.[12]

Ecology, habitat and distribution


The fruit bodies of M. polygramma grow in groups or sub-clusters under hardwoods, particularly deciduous trees such as oak, maple, and basswood. In North America, it has been collected from North Carolina, Massachusetts, New York, and Michigan, where it fruits from June to October.[8] The fruit bodies are susceptible to attack by the parasitic fungi Spinellus fusiger and S. macrocarpus.[13]

Typically found on twigs or buried wood,[11] the fungus is known to be a vigorous decomposer of lignin and cellulose in leaf litter.[14] Mycena polygramma is a saprobic fungus and is one of many fungi that contribute to plant litter decomposition in forest ecosystems through nutrient recycling and humus formation in soil. It is a lignocellulose decomposer of larch litter, and can break down both lignin and carbohydrates, although it has a preference for carbohydrates.[15] In an experiment testing the ability of several litter-decomposing fungi to remove lignin from leaves of the perennial grass Miscanthus sinensis, under pure culture conditions, M. polygramma showed limited ability to cause the mass loss of lignin.[16]

Rare in North America,[8] the fungus is common in Europe, including Great Britain.[10] They have been collected on the Falkland Islands,[17] and Japan.[14]

Chemistry and 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%).[18]

The fungus is one of several dozen Mycena species that are bioluminescent.[19] Unlike most luminescent organisms, M. polygramma has a diurnal rhythm of luminescence intensity and it rises and falls to a light intensity as high as 35 percent. However, this light emission is not typically noticed, as it cannot be detected visually by the dark-adapted eye; sensitive photomultipliers or long exposure times are required to measure the phenomenon.[20] The wavelength of spectral emissions from the fungus grown in pure culture is in the range 470–640 mμ.[21]

See also



  1. ^ a b Dorfelt H, Zschieschang G (1986). "Type studies on several agarics described by F.W. Junghuhn". Mycotaxon. 26: 275–86.
  2. ^ "Mycena polygramma (Bull.) Gray 1821". MycoBank. International Mycological Association. Retrieved 2010-09-26.
  3. ^ Bulliard JBF. (1789). Herbier de la France. Vol. 9. Paris, France: Chez l'auteur, Didot, Debure, Belin. p. plate 395.
  4. ^ Fries EM. (1821). Systema Mycologicum. Vol. 1. Lund, Sweden: Ex Officina Berlingiana. p. 146.
  5. ^ Gray SF. (1821). A Natural Arrangement of British Plants. London, UK: Baldwin, Cradock, and Joy. p. 619.
  6. ^ Rea C. (1922). British Basidiomycetae: a handbook to the larger British fungi. CUP Archive. p. 384.
  7. ^ "Recommended English Names for Fungi in the UK" (PDF). British Mycological Society. Archived from the original (PDF) on 2011-07-16.
  8. ^ a b c d e Smith AH, pp. 292–93.
  9. ^ Griffin DH. (1996). Fungal Physiology. Wiley-Liss. p. 270. ISBN 978-0-471-16615-3.
  10. ^ a b c Jordan M. (2004). The Encyclopedia of Fungi of Britain and Europe. London, UK: Frances Lincoln. p. 169. ISBN 0-7112-2378-5.
  11. ^ a b Phillips R. "Mycena polygramma". Roger's Mushrooms. Archived from the original on 2012-08-11. Retrieved 2010-09-26.
  12. ^ Smith AH. (1937). "Studies in the Genus Mycena. IV". Mycologia. 29 (3): 338–54. doi:10.2307/3754294. JSTOR 3754294.
  13. ^ Atkinson GF. (1900). Studies of American fungi. Mushrooms, Edible, Poisonous, etc. Ithaca, New York: Andrus & Church. pp. 94–5.
  14. ^ a b Osono T, Takeda H (2002). "Comparison of litter decomposing ability among diverse fungi in a cool temperate deciduous forest in Japan". Mycologia. 94 (3): 421–7. doi:10.2307/3761776. JSTOR 3761776. PMID 21156513.
  15. ^ Osonu T, Fukasawa Y, Takeda H (2003). "Roles of diverse fungi in larch needle-litter decomposition". Mycologia. 95 (5): 820–6. doi:10.2307/3762010. JSTOR 3762010. PMID 21148989.
  16. ^ Osono T. (2010). "Decomposition of grass leaves by ligninolytic litter-decomposing fungi". Grassland Science. 56 (1): 31–6. doi:10.1111/j.1744-697X.2009.00170.x.
  17. ^ Pegler DN, Spooner BM, Lewis Smith RI (1980). "Higher Fungi of Antarctica, the Subantarctic Zone and Falkland Islands". Kew Bulletin. 35 (3): 499–562. doi:10.2307/4110020. JSTOR 4110020.
  18. ^ Dembitsky VM, Rezanka T, Shubina EE (1993). "Unusual hydroxy fatty acids from some higher fungi". Phytochemistry. 34 (4): 1057–9. doi:10.1016/S0031-9422(00)90713-1.
  19. ^ Desjardin DE, Oliveira AG, Stevani CV (2008). "Fungi bioluminescence revisited". Photochemical & Photobiological Sciences. 7 (2): 170–82. CiteSeerX doi:10.1039/b713328f. PMID 18264584.
  20. ^ Berliner MD. (1961). "Diurnal periodicity of luminescence in three Basidiomycetes". Science. 134 (3481): 740. Bibcode:1961Sci...134..740B. doi:10.1126/science.134.3481.740. JSTOR 1707391. PMID 17795289. S2CID 21001720.
  21. ^ Berliner MD. (1961). "Studies in fungal luminescence". Mycologia. 53 (1): 84–90. doi:10.2307/3756133. JSTOR 3756133.

Cited books

  • Smith AH. (1947). North American species of Mycena. Ann Arbor, Michigan: University of Michigan Press.