Mycena overholtsii
Encyclopedia
Mycena overholtsii, commonly known as the snowbank fairy helmet or fuzzy foot, is a species of fungus
in the Mycenaceae
family. The mushrooms produced by the fungus are relatively large for the genus Mycena
, with convex grayish caps
up to 5 cm (2 in) in diameter and stems
up to 15 cm (5.9 in) long. The gills on the underside of the cap are whitish to pale gray, and initially closely spaced before becoming well-spaced at maturity after the cap enlarges. The mushrooms are characterized by the dense covering of white "hairs" on the base of the stem. M. overholtsii is an example of a snowbank fungus
, growing on well-decayed conifer logs near snowbanks, during or just after snowmelt
. Formerly known only from high-elevation areas of western North America, particularly the Rocky Mountain and Cascade
regions, it was reported for the first time in Japan in 2010. The edibility
of the mushroom is unknown. M. overholtsii can be distinguished from other comparable species by differences in location, or spore
size.
and Wilhelm Solheim
in 1953, on the basis of specimens collected in the Medicine Bow Mountains
of Albany County, Wyoming. The specific epithet honors the early 20th-century American mycologist Lee Oras Overholts. It is commonly
known as the "snowbank fairy helmet", or "fuzzy foot", although it shares the latter name with Tapinella atrotomentosa
and Xeromphalina campanella
. M. overholtsii has been given the Japanese name yukitsutsumikunugitake.
. They have caps
that are 1.5 to 5 cm (0.590551181102362 to 2 in) in diameter, and convex in shape, developing an umbo
(a central protrusion resembling a nipple) in maturity. The cap surface is smooth, moist, and marked with radial striations. The caps are somewhat hygrophanous
, and depending on age and state of hydration, range in color from brown or grayish-brown, to dark or bluish-gray. The mushroom flesh
is thin and watery, with a light gray color.
The gills have an adnate
, adnexed, or shallowly decurrent
attachment to the stem, and are initially closely spaced before becoming well-spaced at maturity. They have a whitish to pale gray color, and will stain gray when they are bruised. There are three or four tiers of lamellulae (short gills that do not extend fully from the cap margin to the stem) interspersed between the gills. The stem
is 4 to 15 cm (1.6 to 5.9 in) long by 0.3 to 1 cm (0.118110236220472 to 0.393700787401575 in) thick, and tapers upward so that the stem apex is slightly thinner than the base. It can be straight or curved, has cartilage-like flesh, and is hollow in maturity. When growing on soft, well-decayed wood, the stem often penetrates deeply into the substrate
. The stem is pinkish-brown in color, and the lower half is tomentose – densely covered with white, woolly hairs. The mushroom has a yeast-like odor and a mild taste; its edibility
is unknown, but it is not considered poisonous.
, the spore
s appear white. Microscopically, the spores are roughly elliptical, sometimes appearing bean-shaped, with dimensions of 5.5–7.0 by 3.0–3.5 µm
. They are thin-walled and smooth, and bear an indistinct hilar appendage
. The spores are amyloid
, meaning they will absorb iodine
and turn black to blue-black when stained with Melzer's reagent
. The basidia (spore-bearing cells) are four-spored. The cheilocystidia (cystidia on the gill edge), which are scattered and interspersed with basidia, are roughly cylindric to fusoid (spindle-shaped), smooth, hyaline
(translucent), and measure 45–65 by 2–5.5 µm. Pleurocystidia (cystidia on the gill face) are uncommon, and similar in appearance to the cheilocystidia. The cap cuticle
is an ixocutis (a fungal tissue type in which the hypha
e are gelatinous and lay flat) with mostly smooth hyphae that are 1.5–3.5 µm in diameter. The cap flesh is dextrinoid, meaning it will turn reddish-brown in Melzer's reagent. Clamp connection
s are present in the hyphae of M. overholtsii.
and M. galericulata
. The fruit bodies of M. maculata often develop red stains as they mature, but this characteristic is inconsistent and cannot be reliably used for identification. Its spores are larger than that of M. overholtsii, measuring 7–10 by 4–6 µm. M. galericulata is very similar in appearance to M. maculata, but does not undergo reddish staining; its spores are 8–12 by 5.5–9 µm. Another similar species is M. semivestipes
, which can be distinguished by its bleach
-like odor, an eastern North American distribution, fruiting season during summer and autumn, and small spores measuring 4–5 by 2.5–3 µm.
) near melting snowbanks, or sometimes in moist snow chambers formed by receding snow. Cool nighttime temperatures reduce the snowmelt rate, and help ensure that spores released by the mushroom will be dispersed into the soil. The mushroom is common in western North America, particularly the Pacific Northwest
, the Rocky Mountains
and the Cascade mountains
. It has been reported in four US states: South Dakota
, California
, Washington and Wyoming
, but is not known in Oregon
. It is also found in western Canada. The mushroom is restricted to areas with minimum elevations of 1000 m (3,280.8 ft). In 2010, it was reported growing in the boreal coniferous forests of Hokkaido
, Japan, in plantations of Sakhalin fir (Abies sachalinensis), as well as in natural forests dominated by both Sakhalin fir and Jezo spruce
(Picea jezoensis). In North America, the mushroom usually appears between March and July; Japanese collections were made in May. The fruiting period can be prolonged, especially in areas with heavy snowfall, or at high elevations where the snowmelt is delayed.
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
in the Mycenaceae
Mycenaceae
The Mycenaceae are a family of fungi in the order Agaricales. According to the Dictionary of the Fungi , the family contains 10 genera and 705 species. This is one of several families that were separated from the Tricholomataceae as a result of phylogenetic analyses...
family. The mushrooms produced by the fungus are relatively large for the genus Mycena
Mycena
Mycena is a large genus of small saprotrophic mushrooms that are rarely more than a few centimeters in width. They are characterized by a white spore print, a small conical or bell-shaped cap, and a thin fragile stem. Most are gray or brown, but a few species have brighter colors. Most have a...
, with convex grayish caps
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
up to 5 cm (2 in) in diameter and stems
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
up to 15 cm (5.9 in) long. The gills on the underside of the cap are whitish to pale gray, and initially closely spaced before becoming well-spaced at maturity after the cap enlarges. The mushrooms are characterized by the dense covering of white "hairs" on the base of the stem. M. overholtsii is an example of a snowbank fungus
Snowbank fungus
A snowbank fungus is any one of a number of diverse species of fungi that occur adjacent to or within melting snow. They are most commonly found in the mountains of western North America where a deep snowpack accumulates during the winter and slowly melts through the spring and summer, often...
, growing on well-decayed conifer logs near snowbanks, during or just after snowmelt
Snowmelt
In hydrology, snowmelt is surface runoff produced from melting snow. It can also be used to describe the period or season during which such runoff is produced. Water produced by snowmelt is an important part of the annual water cycle in many parts of the world, in some cases contributing high...
. Formerly known only from high-elevation areas of western North America, particularly the Rocky Mountain and Cascade
Cascade Range
The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...
regions, it was reported for the first time in Japan in 2010. The edibility
Edible mushroom
Edible mushrooms are the fleshy and edible fruiting bodies of several species of fungi. Mushrooms belong to the macrofungi, because their fruiting structures are large enough to be seen with the naked eye. They can appear either below ground or above ground where they may be picked by hand...
of the mushroom is unknown. M. overholtsii can be distinguished from other comparable species by differences in location, or spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
size.
History and naming
The species was first described by mycologists Alexander H. SmithAlexander H. Smith
Alexander Hanchett Smith was an American mycologist known for his extensive contributions to the taxonomy and phylogeny of the higher fungi, especially the agarics.-Early life:...
and Wilhelm Solheim
Wilhelm Solheim (botanist)
Wilhelm G. Solheim I was a botanist after whom the Wilhelm G. Solheim Mycological Herbarium at the University of Wyoming is named. His son, Wilhelm G. Solheim II is an archeologist, and in fact is recognized as most senior practitioner of archaeology in Southeast Asia.- Source :...
in 1953, on the basis of specimens collected in the Medicine Bow Mountains
Medicine Bow Mountains
The Medicine Bow Mountains are a mountain range in the Rocky Mountains that extend for from northern Colorado into southern Wyoming. The northern extent of this range is the sub-range the Snowy Range...
of Albany County, Wyoming. The specific epithet honors the early 20th-century American mycologist Lee Oras Overholts. It is commonly
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
known as the "snowbank fairy helmet", or "fuzzy foot", although it shares the latter name with Tapinella atrotomentosa
Tapinella atrotomentosa
Tapinella atrotomentosa, commonly known as the velvet roll-rim or velvet-footed pax, is a species of fungus in the Tapinellaceae family of the Agaricales, or gilled mushrooms. It was originally described as Paxillus atrotomentosus by German naturalist August Batsch, and given its current name by...
and Xeromphalina campanella
Xeromphalina campanella
Xeromphalina campanella is a species of mushroom. The common names of the species include the golden trumpet and the bell Omphalina. The genus name Xeromphalina means "little dry navel" and campanella means "bell-shaped", respectively describing the mature and young shapes of the pileus, or cap...
. M. overholtsii has been given the Japanese name yukitsutsumikunugitake.
Description
Mycena overholtsii produces some of the largest mushrooms of the genus MycenaMycena
Mycena is a large genus of small saprotrophic mushrooms that are rarely more than a few centimeters in width. They are characterized by a white spore print, a small conical or bell-shaped cap, and a thin fragile stem. Most are gray or brown, but a few species have brighter colors. Most have a...
. They have caps
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
that are 1.5 to 5 cm (0.590551181102362 to 2 in) in diameter, and convex in shape, developing an umbo
Umbo (mycology)
thumb|right|[[Cantharellula umbonata]] has an umbo.thumb|right|The cap of [[Psilocybe makarorae]] is acutely papillate.An umbo is a raised area in the center of a mushroom cap. Caps that possess this feature are called umbonate. Umbos that are sharply pointed are called acute, while those that are...
(a central protrusion resembling a nipple) in maturity. The cap surface is smooth, moist, and marked with radial striations. The caps are somewhat hygrophanous
Hygrophanous
The adjective hygrophanous refers to the color change of mushroom tissue as it loses or absorbs water, which causes the pileipellis to become more transparent when wet and opaque when dry....
, and depending on age and state of hydration, range in color from brown or grayish-brown, to dark or bluish-gray. The mushroom flesh
Trama (mycology)
In mycology trama is a term for the inner, fleshy portion of a mushroom's basidiocarp, or fruit body. It is distinct from the outer layer of tissue, known as the pileipellis or cuticle, and from the spore-bearing tissue layer known as the hymenium....
is thin and watery, with a light gray color.
The gills have an adnate
Adnation
Adnation in plants is the "union of unlike parts; organically united or fused with another dissimilar part, e.g. an ovary to a calyx tube, or stamens to petals". This is in contrast to connation, the fusion of similar organs....
, adnexed, or shallowly decurrent
Decurrent
Decurrent is a term used in botany and mycology to describe plant or fungal parts that extend downward.In botany, the term is most often applied to leaf blades that partly wrap or have wings around the stem or petiole and extend down along the stem...
attachment to the stem, and are initially closely spaced before becoming well-spaced at maturity. They have a whitish to pale gray color, and will stain gray when they are bruised. There are three or four tiers of lamellulae (short gills that do not extend fully from the cap margin to the stem) interspersed between the gills. The stem
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
is 4 to 15 cm (1.6 to 5.9 in) long by 0.3 to 1 cm (0.118110236220472 to 0.393700787401575 in) thick, and tapers upward so that the stem apex is slightly thinner than the base. It can be straight or curved, has cartilage-like flesh, and is hollow in maturity. When growing on soft, well-decayed wood, the stem often penetrates deeply into the substrate
Substrate (biology)
In biology a substrate is the surface a plant or animal lives upon and grows on. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock can be substrate for another animal that lives on top of the algae. See also substrate .-External...
. The stem is pinkish-brown in color, and the lower half is tomentose – densely covered with white, woolly hairs. The mushroom has a yeast-like odor and a mild taste; its edibility
Edible mushroom
Edible mushrooms are the fleshy and edible fruiting bodies of several species of fungi. Mushrooms belong to the macrofungi, because their fruiting structures are large enough to be seen with the naked eye. They can appear either below ground or above ground where they may be picked by hand...
is unknown, but it is not considered poisonous.
Microscopic characteristics
Viewed in deposit, as with a spore printSpore print
thumb|300px|right|Making a spore print of the mushroom Volvariella volvacea shown in composite: mushroom cap laid on white and dark paper; cap removed after 24 hours showing pinkish-tan spore print...
, the spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
s appear white. Microscopically, the spores are roughly elliptical, sometimes appearing bean-shaped, with dimensions of 5.5–7.0 by 3.0–3.5 µm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
. They are thin-walled and smooth, and bear an indistinct hilar appendage
Hilum (biology)
In botany, the hilum is a scar or mark left on a seed coat by the former attachment to the ovary wall or to the funiculus...
. The spores are amyloid
Amyloid (mycology)
In mycology the term amyloid refers to a crude chemical test using iodine in either Melzer's reagent or Lugol's solution, to produce a black to blue-black positive reaction. It is called amyloid because starch gives a similar reaction, and that reaction for starch is also called an amyloid reaction...
, meaning they will absorb iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
and turn black to blue-black when stained with Melzer's reagent
Melzer's Reagent
Melzer's reagent is a chemical reagent used by mycologists to assist with the identification of fungi.-Composition:...
. The basidia (spore-bearing cells) are four-spored. The cheilocystidia (cystidia on the gill edge), which are scattered and interspersed with basidia, are roughly cylindric to fusoid (spindle-shaped), smooth, hyaline
Hyaline
The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...
(translucent), and measure 45–65 by 2–5.5 µm. Pleurocystidia (cystidia on the gill face) are uncommon, and similar in appearance to the cheilocystidia. The cap cuticle
Pileipellis
thumb|300px||right|The cuticle of some mushrooms, such as [[Russula mustelina]] shown here, can be peeled from the cap, and may be useful as an identification feature....
is an ixocutis (a fungal tissue type in which the hypha
Hypha
A hypha is a long, branching filamentous structure of a fungus, and also of unrelated Actinobacteria. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium; yeasts are unicellular fungi that do not grow as hyphae.-Structure:A hypha consists of one or...
e are gelatinous and lay flat) with mostly smooth hyphae that are 1.5–3.5 µm in diameter. The cap flesh is dextrinoid, meaning it will turn reddish-brown in Melzer's reagent. Clamp connection
Clamp connection
A clamp connection is a structure formed by growing hyphal cells of certain fungi. It is created to ensure each septum, or segment of hypha separated by crossed walls, receives a set of differing nuclei, which are obtained through mating of hyphae of differing sexual types...
s are present in the hyphae of M. overholtsii.
Similar species
Other similar Mycenas that grow in clusters on wood include M. maculataMycena maculata
Mycena maculata, commonly known as the reddish-spotted Mycena, is a species of fungus in the Mycenaceae family. The fruit bodies, or mushrooms, have conic to bell-shaped to convex caps that are initially dark brown but fade to brownish-gray when young, reaching diameters of up to...
and M. galericulata
Mycena galericulata
Mycena galericulata is a mushroom species commonly known as the common bonnet, the toque mycena, or the rosy-gill fairy helmet. The type species of the genus Mycena was first described scientifically in 1772, but was not considered a Mycena until 1821...
. The fruit bodies of M. maculata often develop red stains as they mature, but this characteristic is inconsistent and cannot be reliably used for identification. Its spores are larger than that of M. overholtsii, measuring 7–10 by 4–6 µm. M. galericulata is very similar in appearance to M. maculata, but does not undergo reddish staining; its spores are 8–12 by 5.5–9 µm. Another similar species is M. semivestipes
Mycena semivestipes
Mycena vestipes is a species of fungus in the Mycenaceae family. First described in 1895 as Omphalina semivestipes by Charles Horton Peck, it was transferred to Mycena in 1947 by Alexander H. Smith....
, which can be distinguished by its bleach
Bleach
Bleach refers to a number of chemicals that remove color, whiten, or disinfect, often via oxidation. Common chemical bleaches include household chlorine bleach , lye, oxygen bleach , and bleaching powder...
-like odor, an eastern North American distribution, fruiting season during summer and autumn, and small spores measuring 4–5 by 2.5–3 µm.
Habitat and distribution
This species is sometimes found singly, but more often in clusters on well-rotted conifer logs and stumps (often Douglas-firDouglas-fir
Douglas-fir is one of the English common names for evergreen coniferous trees of the genus Pseudotsuga in the family Pinaceae. Other common names include Douglas tree, and Oregon pine. There are five species, two in western North America, one in Mexico, and two in eastern Asia...
) near melting snowbanks, or sometimes in moist snow chambers formed by receding snow. Cool nighttime temperatures reduce the snowmelt rate, and help ensure that spores released by the mushroom will be dispersed into the soil. The mushroom is common in western North America, particularly the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
, the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
and the Cascade mountains
Cascade Range
The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...
. It has been reported in four US states: South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, Washington and Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
, but is not known in Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
. It is also found in western Canada. The mushroom is restricted to areas with minimum elevations of 1000 m (3,280.8 ft). In 2010, it was reported growing in the boreal coniferous forests of Hokkaido
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
, Japan, in plantations of Sakhalin fir (Abies sachalinensis), as well as in natural forests dominated by both Sakhalin fir and Jezo spruce
Jezo Spruce
The Jezo spruce or Yezo spruce is a large evergreen tree growing to 30-50 m tall and with a trunk diameter of up to 2 m...
(Picea jezoensis). In North America, the mushroom usually appears between March and July; Japanese collections were made in May. The fruiting period can be prolonged, especially in areas with heavy snowfall, or at high elevations where the snowmelt is delayed.