''Aureoboletus russellii'', commonly known as the jagged-stemmed bolete or Russell's bolete, is a species of

bolete A bolete is a type of mushroom, or fungal fruiting body. It can be identified thanks to a unique cap. On the underside of the cap there is usually a spongy surface with pores, instead of the gills typical of mushrooms. A similar pore surface i ...

fungus in the family

Boletaceae The Boletaceae are a Family (biology), family of mushroom-forming fungi, primarily characterised by small pores on the spore-bearing hymenium, hymenial surface (at the underside of the mushroom), instead of Lamella (mycology), gills as are found ...

. 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 ...

are characterized by their coarsely shaggy

stem Stem or STEM most commonly refers to: * Plant stem, a structural axis of a vascular plant * Stem group * Science, technology, engineering, and mathematics Stem or STEM can also refer to: Language and writing * Word stem, part of a word respon ...

. The yellow-brown to reddish-brown

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 ...

are initially velvety, but become cracked into patches with age. An

edible An edible item is any item that is safe for humans to eat. "Edible" is differentiated from " eatable" because it does not indicate how an item tastes, only whether it is fit to be eaten. Nonpoisonous items found in nature – such as some mushroo ...

species, it is found in Asia and eastern North America, where it grows in a

mycorrhizal A mycorrhiza (; , 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's rhizosphere, the plant root system and its surroundings. Mycorrhizae play ...

association with

oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

, hemlock, and

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. ''World Flora Online'' accepts 134 species-rank taxa (119 species and 15 nothospecies) of pines as cu ...

trees.

Taxonomy

Originally named ''Boletus russellii'' by

Charles Christopher Frost Charles Christopher Frost (November 11, 1805 – March 16, 1880) was an American mycologist. He described several species of fungi from the New England area of the United States. In one paper, Frost described 22 new species of boletes, and he wa ...

in 1878 from collections made in

New England New England is a region consisting of six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the ...

, the species was transferred to '' Boletellus'' by Edouard-Jean Gilbert in 1931. It was then transferred to ''

Aureoboletus ''Aureoboletus'' is a genus of bolete fungi in the family Boletaceae. It was circumscription (taxonomy), circumscribed by Czech mycologist Zdeněk Pouzar in 1957. A taxonomic monograph was published in 2010 by Wolfgang Klofac. At least 11 species ...

'' by Gang Wu and Zhu L. Yang in 2016. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''russellii'' honors American botanist and Unitarian minister

John Lewis Russell John Lewis Russell (2 December 1808 – 7 June 1873) was an American botany, botanist and Unitarianism, Unitarian minister. Born in Salem, Massachusetts, Russell attended Harvard University and received his early education in Salem, Newburyport an ...

, the first collector of the species.

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 con ...

s given to the mushroom include shagnet, jagged-stem bolete, and Russell's bolete.

Description

The

cap A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. The origin of the word "cap" comes from the Old French word "chapeau" which means "head co ...

is hemispheric to convex or broadly convex, reaching a diameter of . The cap surface is initially velvety, with a margin rolled inward, but after maturing the cap becomes cracked and forms scale-like patches. The color is yellow-brown to reddish-brown to olive-gray, while 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 muscles, fats and other loose connective tissues, ...

is pale yellow to yellow. The pore surface is yellow to greenish yellow; when the pore surface is rubbed or injured it will turn a brighter yellow color. The pores are angular, and about 1 mm wide, while the tubes that comprise the pores are up to deep. The

is up to long and thick, and either roughly equal in width throughout, or slightly thicker at the base. Reddish brown to pinkish tan in color, the stem is solid (i.e. not hollow or stuffed with a pith), sometimes curved and viscid at the base. The surface texture is characterized by deep grooves and ridges, with the ridges torn and branched so as to appear shaggy. No

partial veil In mycology, a partial veil (also called an inner veil, to differentiate it from the "outer", or universal veil) is a temporary structure of tissue found on the fruiting bodies of some Basidiomycota, basidiomycete fungus, fungi, typically agarics. ...

ring (The) Ring(s) may refer to: * Ring (jewellery), a round band, usually made of metal, worn as ornamental jewelry * To make a sound with a bell, and the sound made by a bell Arts, entertainment, and media Film and TV * ''The Ring'' (franchise), a ...

are present. 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 warm orange ("tussock") color spore print. ...

is olive brown. The

spores In biology, a spore is a unit of sexual (in fungi) 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 plant ...

are ellipsoid, measuring 15–20 by 7–11

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

. Similar to the reticulation of the stem, the spore surfaces have deep longitudinal grooves and furrows, sometimes with a cleft in the wall at the top of the spore.

Similar species

Aureoboletus betula ''Aureoboletus betula'' is a species of mushroom producing fungus in the family Boletaceae. It is commonly known as the shaggy-stalked bolete. Taxonomy It was first described in 1822 by the German-American mycologist Lewis David de Schweinit ...

'' is somewhat similar in stature and also has a deeply reticulate stem, but can be distinguished by its smooth, shinier cap and spores with pits. ''

Boletellus ananas ''Boletellus ananas'', commonly known as the pineapple bolete, is a mushroom in the family Boletaceae, and the type species of the genus ''Boletellus''. Previously known as ''Boletus ananas'' and ''Boletus coccinea'' (among other synonym (taxo ...

'' is somewhat similar.

Habitat and distribution

''Aureoboletus russellii'' is known from eastern North America, where it grows singly or scattered on the ground in association with

, hemlock, and

trees. The geographic range extends from eastern Canada south to Central America, and west to

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

and southern

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

. It is also found in Asia, including Korea and Taiwan.

Uses

The fruit bodies are

, but of low culinary interest due to being soft and little flavour.

References