''Russula crustosa'', commonly known as the crusty russula, 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

Russulaceae The Russulaceae are a diverse family of fungi in the order Russulales, with roughly 1,900 known species and a worldwide distribution. They comprise the brittlegills and the milk-caps, well-known mushroom-forming fungi that include some edible ...

. It is found in Asia and North America.

Taxonomy

The species was first described scientifically by American mycologist

Charles Horton Peck Charles Horton Peck (March 30, 1833 – July 11, 1917) was an American mycologist of the 19th and early 20th centuries. He was the New York State Botanist from 1867 to 1915, a period in which he described over 2,700 species of North American fun ...

in 1886, who made the type collections in

Day, New York Day is a town in Saratoga County, New York, United States. The Town of Day is in the northwestern part of the county and is northeast of Amsterdam. Day is located inside the Adirondack Park. History The town was first settled around 1797. ...

. It is classified in the subsection ''Virescentinae'' of the genus ''Russula''. 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 ...

''crustosa'' means "with a rind".

Common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

s for the species include "crusty Russula", "green quilt Russula", and "encrusted Russula".

Description

The

fruit bodies The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life cyc ...

have

caps Caps are flat headgear. Caps or CAPS may also refer to: Science and technology Computing * CESG Assisted Products Service, provided by the U.K. Government Communications Headquarters * Composite Application Platform Suite, by Java Caps, a Java ...

that are initially convex before flattening out in age, often developing a central depression, and measure in diameter. In maturity, the dry cap surface breaks up into greenish patches around the margin. The margin of the cap has radial grooves that match the

gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

on the underside. The closely spaced gills are white, cream, or pale yellow in color, and have an

adnate Adnate may refer to: * Adnation, in botany, the fusion of two or more whorls of a flower * Adnate, in mycology, a classification of lamellae (gills) * Conjoined twins Conjoined twins – sometimes popularly referred to as Siamese twins – are ...

attachment to the stem. Measuring long by thick, the stem is white to pale yellow, and becomes hollow in age. The

flesh Flesh is any aggregation of soft tissues of an organism. Various multicellular organisms have soft tissues that may be called "flesh". In mammals, including humans, ''flesh'' encompasses muscle Skeletal muscles (commonly referred to as mu ...

is hard and compact (when young), and whitish. The

spore print 300px, Making a spore print of the mushroom ''Volvariella volvacea'' shown in composite: (photo lower half) mushroom cap laid on white and dark paper; (photo upper half) cap removed after 24 hours showing pinkish-tan spore print. A 3.5-centimeter ...

is pale

buff Buff or BUFF may refer to: People * Buff (surname), a list of people * Buff (nickname), a list of people * Johnny Buff, ring name of American world champion boxer John Lisky (1888–1955) * Buff Bagwell, a ring name of American professional wr ...

, and 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 elliptic in shape, and somewhat warted with a few fine interconnecting lines. They are

hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

(translucent),

amyloid Amyloids are aggregates of proteins characterised by a Fibril, fibrillar morphology of 7–13 Nanometer, nm in diameter, a beta sheet (β-sheet) Secondary structure of proteins, secondary structure (known as cross-β) and ability to be Staining, ...

, and measure 6–9 by 5.5–7 μm. An

edible mushroom Edible mushrooms are the fleshy and edible fruit bodies of several species of macrofungi (fungi which bear fruiting structures that are large enough to be seen with the naked eye). They can appear either below ground (hypogeous) or above ground ...

, ''R. crustosa'' has no distinguishing odor, and a taste ranging from mild to slightly acrid. Other greenish Russulas, including '' R. subgraminicolor'', '' R. aeruginea'', and '' R. variata'', can be most readily distinguished by their non-cracking cap surfaces.

Similar species

''Russula crustosa'' is commonly mistaken for ''

Russula virescens ''Russula virescens'' is a basidiomycete mushroom of the genus ''Russula'', and is commonly known as the green-cracking russula, the quilted green russula, or the green brittlegill. It can be recognized by its distinctive pale green cap that ...

'', a more desirable edible mushroom that features greenish patches on its cap surface. The latter species has flesh that breaks apart more readily, and a white spore print.

Ecology and distribution

''Russula crustosa'' is a

mycorrhiza A mycorrhiza (from Greek μύκης ', "fungus", and ῥίζα ', "root"; pl. mycorrhizae, mycorrhiza or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the plant ...

l fungus and associated with

broadleaf trees A broad-leaved, broad-leaf, or broadleaf tree is any tree within the diverse botanical group of angiosperms that has flat leaves and produces seeds inside of fruits. It is one of two general types of trees, the other being a conifer, a tree with n ...

, particularly

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 ...

and

hickory Hickory is a common name for trees composing the genus ''Carya'', which includes around 18 species. Five or six species are native to China, Indochina, and India (Assam), as many as twelve are native to the United States, four are found in Mexi ...

. The fruit bodies grow on the ground in

mixed forest Temperate broadleaf and mixed forest is a temperate climate terrestrial habitat type defined by the World Wide Fund for Nature, with broadleaf tree ecoregions, and with conifer and broadleaf tree mixed coniferous forest ecoregions. These for ...

s singly, scattered, or in groups. Fruiting occurs between June and December. The

pleasing fungus beetle ''Ischyrus quadripunctatus'' Erotylidae, or the pleasing fungus beetles, is a family of beetles belonging to Cucujoidea containing over 100 genera. In the present circumscription, it contains 6 tribes (Tritomini, Dacnini, Megalodacnini, Ero ...

species '' Tritoma angulata'' is known to feed on the fruit bodies. In North America, the mushroom is common, and widespread in the southeastern United States. In Asia, ''Russula crustosa'' is found in China, India, Malaysia, and Thailand.

References

External links