''Mycena fonticola'' is a species of

fungus A fungus ( : fungi or funguses) is any member of the 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, separately from th ...

in the family

Mycenaceae The Mycenaceae are a family of fungi in the order Agaricales. According to the ''Dictionary of the Fungi'' (10th edition, 2008), the family contains 10 genera and 705 species. This is one of several families that were separated from the Tricholom ...

. First reported in 2007, it is known only from central

Honshu , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island separ ...

, in Japan, where it grows on dead leaves and twigs in low-elevation forests dominated by

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

trees. The

fruit body In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the Ovary (plants), ovary after flowering plant, flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their ...

of the fungus has a smooth, violet-brown cap up to in diameter, and a slender

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

up to long. Distinguishing microscopic characteristics of the mushroom include the relatively large, distinctly amyloid spores (turning blue to black when

stained A stain is a discoloration that can be clearly distinguished from the surface, material, or medium it is found upon. They are caused by the chemical or physical interaction of two dissimilar materials. Accidental staining may make materials app ...

with Melzer's reagent), the smooth, spindle-shaped cheilocystidia ( cystidia on the gill edge), the absence of pleurocystidia (cystidia on the gill face), the diverticulate hyphae of the

cap cuticle The pileipellis is the uppermost layer of hyphae in the pileus of a fungal fruit body. It covers the trama, the fleshy tissue of the fruit body. The pileipellis is more or less synonymous with the cuticle, but the cuticle generally describes th ...

, and the absence of clamp connections.

Taxonomy, naming, and classification

The fungus was first collected by Japanese mycologist Haruki Takahashi in 1999, and described as a new species along with seven other Japanese Mycenas in a 2007 publication. The mushroom's Japanese name is ''Izumino-ashinagatake'' (イズミノアシナガタケ). The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''fonticola'' is derived from

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

, and means "dweller in fountain". According to Takahashi, various macro- and microscopic features suggest that this species is best classified in the section ''Fragilipedes'' (Fr.) Quél., as defined by the Dutch ''Mycena'' specialist Maas Geesteranus.

Description

The cap is in diameter, and ranges in shape from conical to convex to bell-shaped. The surface has radially arranged shallow grooves extending almost to the center of the cap. The cap surface is somewhat hygrophanous (changing color as it loses or absorbs water), dry, and smooth. It is colored violet-brown when young, then becomes somewhat paler from the margin. The white flesh is up to 1 mm thick, and lacks any distinctive odor or taste. The

is long and slender compared to the size of the cap, typically tall by thick, cylindrical, slightly enlarged at the base, and hollow. It is grayish-brown to violet-brown at the top, gradually becoming violet-brown on the lower portion. The stem surface is initially

pruinose Pruinescence , or pruinosity, is a "frosted" or dusty-looking coating on top of a surface. It may also be called a pruina (plural: ''pruinae''), from the Latin word for hoarfrost. The adjectival form is pruinose . Entomology In insects, a "blo ...

(appearing to be covered with a fine whitish powder), but becomes smooth in age. The stem base bears large, bristle-like coarse white hairs. The gills are adnexed (narrowly attached to the stem), with between 23 and 27 reaching the stem. The gills are up to broad, thin, and have a whitish or with a grayish hue; the gills edges are the same color as the gill faces.

Microscopic characteristics

The

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

s are

ellipsoid An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the ...

, smooth, colorless, distinctly amyloid (absorbing iodine stain from Melzer's reagent), thin-walled, and measure 11.5–14 by 6–8

µm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

. The spore-bearing cells, the basidia, are 17–28 by 6–8 µm, club-shaped, and four-spored. The basidioles (immature or aborted basidia) are club-shaped. The cheilocystidia ( cystidia found on the gills edges) are 32–39 by 5–12 µm, abundant, spindle-shaped to roughly club-shaped, often apically broadly rounded, smooth, colorless, and thin-walled. They form a sterile gill edge. Pleurocystidia (cystidia on the gill faces) are absent in this species. The hymenophoral tissue (tissue of the

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some ...

-bearing structure) is made of thin-walled hyphae that are 7–15 µm wide, cylindrical, smooth, colorless, and

dextrinoid In mycology a tissue or feature is said to be amyloid if it has a positive amyloid reaction when subjected to a crude chemical test using iodine as an ingredient of either Melzer's reagent or Lugol's solution, producing a blue to blue-black staini ...

(staining reddish to reddish-brown in Melzer's reagent). The

is made of parallel, bent-over hyphae that are 2–5 µm wide, cylindrical, and densely covered with warty or finger-like thin-walled diverticulae that are colorless or contain cytoplasmic brownish pigment. The layer of hyphae underlying the cap cuticle are parallel, colorless or with cytoplasmic brownish pigment, dextrinoid, and have short and inflated cells measuring up to 30 µm wide. The stem cuticle is made of parallel, bent-over hyphae that are 3–5 µm wide, and cylindrical. These hyphae are covered with scattered, thin-walled warty or finger-like diverticulae that can be either colorless, or contain brownish

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

in the

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

. The flesh of the stem is made of longitudinally running, cylindrical hyphae that are 5–17 µm wide, smooth, colorless, and dextrinoid. Clamp connections are absent in all tissues of this species.

Similar species

'' Mycena mustea'' is another similar ''Mycena'' that was discovered and reported concurrently with ''M. fonticola''; it differs in forming a pale grayish purple cap with a low and broad umbo. Microscopically, it has club-shaped cheilocystidia with several apical short finger-like outgrowths, and nondiverticulate hyphae in the stem cuticle.

Habitat and distribution

''Mycena fonticola'' is known only from Kanagawa, Japan. Fruit bodies are found solitary or scattered, on dead leaves and twigs in low-elevation forests dominated by the

species ''

Quercus myrsinaefolia ''Quercus myrsinifolia'' is an Asian species of tree in the ring-cupped oaks subgenus of the family Fagaceae. It has several common names, including bamboo-leaf oak, Chinese evergreen oak, and Chinese ring-cupped oak. Its Chinese name is ; piny ...

'' and '' Q. serrata''.

References

External links

The Agaricales in Southwestern Islands of Japan
Images of the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

specimen {{Taxonbar, from=Q5576275 fonticola Fungi of Asia Fungi described in 2007