Boletus zelleri
Encyclopedia
Boletus zelleri, commonly known as Zeller's Bolete, is an edible
species of mushroom
in the family Boletaceae
. First described scientifically by American mycologist William Alphonso Murrill in 1912, the species has been juggled by various authors to several genera
, including Boletus
, Boletellus
, and Xerocomus
. Found solely in western North America from British Columbia
south to Mexico
, the fruit bodies are distinguished by their dark reddish brown to nearly black caps
with uneven surfaces, the yellow pores on the underside of the caps, and the red-streaked yellow stems
. The fungus grows in summer and autumn on the ground, often in Douglas fir forests or on their margins. The development of the fruit bodies
is gymnocarpic, meaning that the hymenium
appears and develops to maturity in an exposed state, not enclosed by any protective membrane.
. Murrill named it Ceriomyces zelleri before switching the genus later that year to Boletus
. In 1944, Walter Henry Snell thought the taxon would be more appropriate in the genus Xerocomus
. In 1959, mycologists Rolf Singer
, Snell and Esther A. Dick transferred the species to Boletellus
, explaining that the microstructure of the trama
and the faint ornamentation of the spores were inconsistent with placement in Xerocomus
. American mycologist Harry D. Thiers
, in his 1976 monograph
on North American boletes, claimed that he failed to consistently find ornamentation on the spores of material he collected, and preferred to retain the species in Boletus.
The specific epithet zelleri was chosen by Murrill to honor Professor Sanford Myron Zeller
, mycologist at Oregon State University
. Zeller accompanied Murrill in his Seattle expedition, and discovered the first specimens of the mushroom.
is typically between 5 – in diameter, initially convex but flattening somewhat in maturity. It is fleshy, with an uneven velvety surface, and dark brown to nearly black; the margin of the cap is a pale cream color. Young specimens are covered by a grayish bloom.
The tubes that comprise the undersurface of the cap (the hymenium
) are up to 1.5 cm (0.590551181102362 in) long and angular, yellow, becoming dirty yellow and finally greenish-yellow; there are 1–2 pores per millimeter on the hymenium surface. They do not change color when bruised, although they may turn slightly brownish when exposed to the air for a time. The flesh
is yellow to dirty yellow, up to 1.5 cm (0.590551181102362 in) thick, and inconsistently bruises blue when cut or broken. The stem
is up to 10 cm (3.9 in) tall, 1 – thick, and swollen toward the base. The stem surface is red or yellowish with red lines, often white or yellow at the base, and solid (that is, not hollow), with fibrous flesh; in maturity the stem ages to yellowish-red to dark red. The spore print
is olive-brown; one source notes that creating a spore print may result in "a lot of yellow juice on the paper".
, although occasionally there will be some "giant spores" with lengths of up to 24 µm. The basidia, the spore-bearing cells, are 26–35 by 9.5–12 µm, and four-spored. The cystidia are roughly cylindrical and thin-walled, with dimensions of 38–77 by 5.5–14.8 µm. There are no clamp connection
s present in the hypha
e.
species, although care should be taken to ensure that specimens collected for consumption are free of fly larvae. There is no distinguishable odor, and the taste is alternately described as pleasant, mild, or "slightly acidic". The original species description noted that the texture was "slightly mucilaginous". The mushroom is suitable for preserving or drying. It is harvested and sold commercially in local markets in British Columbia, Canada.
, found only in eastern North America, has a velvety to smooth, dark reddish brown, cracked cap with pale exposed flesh.
appears and develops to maturity in an exposed state, not enclosed by any protective membrane. In this type of development, the cap is formed from hyphae at the top of the stem and subsequently expands by growth along the margins; the hymenium forms later beneath the cap in an direction away from the center.
The mushrooms originate as minute fruit bodies (called "pins" due to their shape) from a yellow mycelium that forms a mat and tends to engulf pine needles. The pins, typically 1–2 mm in diameter, lengthen vertically until they are roughly three or four times longer than they are thick. Until this point, the fruit body is a homogenous mass of tissue. It differentiates simultaneously into cap and stem along a cleavage plane (an axis along which any cell division occurs) from the outside inward, which gives rise to deep furrow encircling the fruit body. The hymenium is formed in the roof of this furrow, growing inward and upward from the outside edge. The cap develops from the upper section of this division, the stem from the lower.
in mature coniferous forests, occasionally abundant on grassy edges of the forest, rarely on badly decayed conifer logs. It is an ectomycorrhizal mushroom, meaning that the fungal hypha
e form sheaths around the rootlets of certain trees, exchanging nutrients with them in a mutualistic relationship. The fungus associates with alder
, poplar
and other hardwood
s, and has been shown in laboratory culture
to form ectomycorrhizae with Western Hemlock (Tsuga heterophylla). However, it has also been noted to grow around California Redwood, a tree not known to form mycorrizhae. It is known to form long rhizomorphs (aggregations of hyphae that resemble roots), and has been noted to be more abundant in sites with buried wood than without. In British Columbia, it occurs from summer to early winter, although it also appears infrequently in early spring. In California, the mushroom often fruits after the rainy period in autumn through to March or April. The dark coloring of the cap make this species difficult to notice, "unless a glimpse of the yellow hymenium is obtained".
Boletus zelleri is distributed in North America in the Pacific Northwest
south to California and Mexico. It has also been reported from Tibet
, but this may be based on a misidentification.
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...
species of mushroom
Mushroom
A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...
in the family Boletaceae
Boletaceae
Boletaceae are a family of mushrooms, primarily characterized by developing their spores in small pores on the underside of the mushroom, instead of gills, as are found in agarics. Nearly as widely distributed as agarics, they include the Cep or King Bolete , much sought after by mushroom hunters...
. First described scientifically by American mycologist William Alphonso Murrill in 1912, the species has been juggled by various authors to several genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
, including Boletus
Boletus
Boletus is a genus of mushroom, comprising over 100 species. The genus Boletus was originally broadly defined and described by Elias Magnus Fries in 1821, essentially containing all fungi with pores...
, Boletellus
Boletellus
Boletellus is a genus of fungi in the family Boletaceae. The genus has a widespread distribution, especially in subtropical regions, and contains about 50 species. The genus was first described by American mycologist William Alphonso Murrill in 1909...
, and Xerocomus
Xerocomus
Xerocomus is a genus of fungi which is closely related to Boletus. Many mycologists do not recognize the distinction.Most members of Xerocomus are edible.Ladurner and Simonini published a monograph on Xerocomus in 2003....
. Found solely in western North America from British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
south to Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, the fruit bodies are distinguished by their dark reddish brown to nearly black 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...
with uneven surfaces, the yellow pores on the underside of the caps, and the red-streaked yellow 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...
. The fungus grows in summer and autumn on the ground, often in Douglas fir forests or on their margins. The development of the fruit bodies
Basidiocarp
In fungi, a basidiocarp, basidiome or basidioma , is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do not produce such structures...
is gymnocarpic, meaning that the hymenium
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 cells develop into sterile cells called cystidia or...
appears and develops to maturity in an exposed state, not enclosed by any protective membrane.
Taxonomy
Boletus zelleri was first described by American mycologist William Alphonso Murrill in 1912, based on specimens he found on the campus of the University of WashingtonUniversity of Washington
University of Washington is a public research university, founded in 1861 in Seattle, Washington, United States. The UW is the largest university in the Northwest and the oldest public university on the West Coast. The university has three campuses, with its largest campus in the University...
. Murrill named it Ceriomyces zelleri before switching the genus later that year to Boletus
Boletus
Boletus is a genus of mushroom, comprising over 100 species. The genus Boletus was originally broadly defined and described by Elias Magnus Fries in 1821, essentially containing all fungi with pores...
. In 1944, Walter Henry Snell thought the taxon would be more appropriate in the genus Xerocomus
Xerocomus
Xerocomus is a genus of fungi which is closely related to Boletus. Many mycologists do not recognize the distinction.Most members of Xerocomus are edible.Ladurner and Simonini published a monograph on Xerocomus in 2003....
. In 1959, mycologists Rolf Singer
Rolf Singer
Rolf Singer was a German-born mycologist and one of the most important taxonomists of gilled mushrooms in the 20th century....
, Snell and Esther A. Dick transferred the species to Boletellus
Boletellus
Boletellus is a genus of fungi in the family Boletaceae. The genus has a widespread distribution, especially in subtropical regions, and contains about 50 species. The genus was first described by American mycologist William Alphonso Murrill in 1909...
, explaining that the microstructure of the trama
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....
and the faint ornamentation of the spores were inconsistent with placement in Xerocomus
Xerocomus
Xerocomus is a genus of fungi which is closely related to Boletus. Many mycologists do not recognize the distinction.Most members of Xerocomus are edible.Ladurner and Simonini published a monograph on Xerocomus in 2003....
. American mycologist Harry D. Thiers
Harry D. Thiers
Harry Delbert Thiers, born January 22, 1919 in Fort McKavett, Texas, died August 8, 2000 in Ohio, was an American mycologist who studied and named a great many fungi of native to North America, particularly California. Thiers taught mycology at San Francisco State University for many years, and a...
, in his 1976 monograph
Monograph
A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...
on North American boletes, claimed that he failed to consistently find ornamentation on the spores of material he collected, and preferred to retain the species in Boletus.
The specific epithet zelleri was chosen by Murrill to honor Professor Sanford Myron Zeller
Sanford Myron Zeller
Sanford Myron Zeller was an American mycologist. Born in Coldwater, Michigan, Zeller was educated at Lawrence College in Wisconsin, then Greenville College in Illinois, from which he received a Bachelor of Science degree in 1909. He earned his doctorate in botany in 1917 at Washington University...
, mycologist at Oregon State University
Oregon State University
Oregon State University is a coeducational, public research university located in Corvallis, Oregon, United States. The university offers undergraduate, graduate and doctoral degrees and a multitude of research opportunities. There are more than 200 academic degree programs offered through the...
. Zeller accompanied Murrill in his Seattle expedition, and discovered the first specimens of the mushroom.
Description
The capPileus (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...
is typically between 5 – in diameter, initially convex but flattening somewhat in maturity. It is fleshy, with an uneven velvety surface, and dark brown to nearly black; the margin of the cap is a pale cream color. Young specimens are covered by a grayish bloom.
The tubes that comprise the undersurface of the cap (the hymenium
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 cells develop into sterile cells called cystidia or...
) are up to 1.5 cm (0.590551181102362 in) long and angular, yellow, becoming dirty yellow and finally greenish-yellow; there are 1–2 pores per millimeter on the hymenium surface. They do not change color when bruised, although they may turn slightly brownish when exposed to the air for a time. The 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 yellow to dirty yellow, up to 1.5 cm (0.590551181102362 in) thick, and inconsistently bruises blue when cut or broken. 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 up to 10 cm (3.9 in) tall, 1 – thick, and swollen toward the base. The stem surface is red or yellowish with red lines, often white or yellow at the base, and solid (that is, not hollow), with fibrous flesh; in maturity the stem ages to yellowish-red to dark red. The spore print
Spore 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...
is olive-brown; one source notes that creating a spore print may result in "a lot of yellow juice on the paper".
Microscopic characteristics
The spores are ellipsoid in shape, smooth, and have dimensions of 12–16 by 4–6 µmMicrometre
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...
, although occasionally there will be some "giant spores" with lengths of up to 24 µm. The basidia, the spore-bearing cells, are 26–35 by 9.5–12 µm, and four-spored. The cystidia are roughly cylindrical and thin-walled, with dimensions of 38–77 by 5.5–14.8 µm. There are no 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 present in 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.
Edibility
Boletus zelleri is an edibleEdible 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...
species, although care should be taken to ensure that specimens collected for consumption are free of fly larvae. There is no distinguishable odor, and the taste is alternately described as pleasant, mild, or "slightly acidic". The original species description noted that the texture was "slightly mucilaginous". The mushroom is suitable for preserving or drying. It is harvested and sold commercially in local markets in British Columbia, Canada.
Similar species
The red-cracked bolete (Boletus chrysenteron) has an olive-brown cap that cracks, exposing flesh that ages to pinkish red. Boletellus chrysenteroidesBoletellus chrysenteroides
Boletellus chrysenteroides is a species of fungus in the family Boletaceae. It was first described as Boletus chrysenteroides by mycologist Wally Snell in 1936. Snell later transferred the species to Boletellus....
, found only in eastern North America, has a velvety to smooth, dark reddish brown, cracked cap with pale exposed flesh.
Fruit body development
In 1914, Zeller published a study of the development of the mushroom, made possible by the prolific fruiting of the fungus in Seattle in the fall of 1912. Development was studied by examining thin sections of tissues in different stages of development, and the differentiation of tissues and structures followed by using histological stains. The growth form of Boletus zelleri is called gymnocarpic, meaning that the hymeniumHymenium
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 cells develop into sterile cells called cystidia or...
appears and develops to maturity in an exposed state, not enclosed by any protective membrane. In this type of development, the cap is formed from hyphae at the top of the stem and subsequently expands by growth along the margins; the hymenium forms later beneath the cap in an direction away from the center.
The mushrooms originate as minute fruit bodies (called "pins" due to their shape) from a yellow mycelium that forms a mat and tends to engulf pine needles. The pins, typically 1–2 mm in diameter, lengthen vertically until they are roughly three or four times longer than they are thick. Until this point, the fruit body is a homogenous mass of tissue. It differentiates simultaneously into cap and stem along a cleavage plane (an axis along which any cell division occurs) from the outside inward, which gives rise to deep furrow encircling the fruit body. The hymenium is formed in the roof of this furrow, growing inward and upward from the outside edge. The cap develops from the upper section of this division, the stem from the lower.
Habitat and distribution
This species grows solitarily or in small groups on the ground or in forest duffForest floor
The forest floor, also called detritus, duff and the O horizon, is one of the most distinctive features of a forest ecosystem. It mainly consists of shed vegetative parts, such as leaves, branches, bark, and stems, existing in various stages of decomposition above the soil surface...
in mature coniferous forests, occasionally abundant on grassy edges of the forest, rarely on badly decayed conifer logs. It is an ectomycorrhizal mushroom, meaning that the fungal 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 form sheaths around the rootlets of certain trees, exchanging nutrients with them in a mutualistic relationship. The fungus associates with alder
Alder
Alder is the common name of a genus of flowering plants belonging to the birch family . The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate Zone and in the Americas along the Andes southwards to...
, poplar
Poplar
Populus is a genus of 25–35 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar , aspen, and cottonwood....
and other hardwood
Hardwood
Hardwood is wood from angiosperm trees . It may also be used for those trees themselves: these are usually broad-leaved; in temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen.Hardwood contrasts with softwood...
s, and has been shown in laboratory culture
Microbiological culture
A microbiological culture, or microbial culture, is a method of multiplying microbial organisms by letting them reproduce in predetermined culture media under controlled laboratory conditions. Microbial cultures are used to determine the type of organism, its abundance in the sample being tested,...
to form ectomycorrhizae with Western Hemlock (Tsuga heterophylla). However, it has also been noted to grow around California Redwood, a tree not known to form mycorrizhae. It is known to form long rhizomorphs (aggregations of hyphae that resemble roots), and has been noted to be more abundant in sites with buried wood than without. In British Columbia, it occurs from summer to early winter, although it also appears infrequently in early spring. In California, the mushroom often fruits after the rainy period in autumn through to March or April. The dark coloring of the cap make this species difficult to notice, "unless a glimpse of the yellow hymenium is obtained".
Boletus zelleri is distributed in North America in 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...
south to California and Mexico. It has also been reported from Tibet
Tibet
Tibet is a plateau region in Asia, north-east of the Himalayas. It is the traditional homeland of the Tibetan people as well as some other ethnic groups such as Monpas, Qiang, and Lhobas, and is now also inhabited by considerable numbers of Han and Hui people...
, but this may be based on a misidentification.
External links
- Boletus zelleri at Mushroom Observer - Photographs