Suillus spraguei
Encyclopedia
Suillus spraguei is a species of fungus
in the Suillaceae
family. It is known by a variety of common name
s, including the painted slipperycap, the painted suillus or the red and yellow suillus. Suillus spraguei has had a complex taxonomical
history, and is also frequently referred to Suillus pictus in the literature. The readily identifiable fruit bodies
have caps
that are dark red when fresh, dry to the touch, and covered with mats of hairs and scales that are separated by yellow cracks. On the underside of the cap are small, yellow, angular pores that become brownish as the mushroom ages. The stalk
bears a grayish cottony ring
, and is typically covered with soft hairs or scales.
Suillus spraguei grows in a mycorrhizal association with several pine
species, particularly eastern white pine
, and the fruit bodies grow on the ground, appearing from early summer to autumn. It has a disjunct distribution
, and is found in eastern Asia, northeastern North America, and Mexico throughout the range of the host tree. The mushroom is edible
, although opinions about its quality vary. The mushroom bears a resemblance to several other Suillus
species, including the closely related S. decipiens
, although the species can be differentiated by variations in color and size.
history. Although the first specimen was originally collected in New England
in 1856 by Charles James Sprague, a formal scientific description
was not published until 1872 when Miles Joseph Berkeley
and Moses Ashley Curtis
called it Boletus spraguei. In a publication that appeared the following year, American mycologist Charles Horton Peck
named the species Boletus pictus. Berkeley and Curtis had also described what they believed to be a new species—Boletus murraii—although this was later considered by Rolf Singer
to be merely a younger version of their Boletus spraguei. Although Peck's description appeared in print in 1873, the date stamp on the original publication revealed that he had sent his documents to the printer before the appearance of the 1872 Berkeley and Curtis publication, thus establishing nomenclatural priority
under the rules of fungal naming. However, in 1945 Singer reported that the name Boletus pictus was illegitimate because it was a homonym
, already being used for a polypore
mushroom described by Carl Friedrich Schultz in 1806. The name was officially switched to Suillus spraguei in 1986 (Otto Kuntze
had previously transferred the taxon to Suillus in 1898).
A 1996 molecular analysis of 38 Suillus species used the sequences of their internal transcribed spacer
s to infer phylogenetic relationships and clarify the taxonomy
of the genus. The results indicate that S. spraguei is most closely related to S. decipiens
. The species S. granulatus
and S. placidus
lie on a branch sister to that containing S. spraguei. These results were corroborated and extended in later publications that assessed the relationships between Asian and eastern North American isolates of various Suillus, including S. spraguei. The analysis supported the hypothesis that Chinese and U.S. S. spraguei and S. decipiens were each others' closest relatives, and the clade
that contained them could be divided into four distinct subgroups: S. decipiens, U.S. S. spraguei, China (Yunnan
) S. spraguei, and China (Jilin
) S. spraguei.
The specific epithet spraguei is an homage to the collector Sprague, while pictus means "painted" or "colored". Suillus spraguei is commonly known
as the "painted slipperycap", the "painted suillus", or the "red and yellow suillus". It is also called the "eastern painted Suillus" to contrast with the "western painted Suillus" (Suillus lakei
).
of the fruit body
is 3 to 12 cm (1.2 to 4.7 in) in diameter, and depending on its age, is either conic to convex, to somewhat flattened at maturity. The cap margin is initially rolled downward before straightening out, often with hanging remnants of partial veil (appendiculate). The cap surface is covered with densely matted filaments that are rough and scale-like. The scales are pink to brownish red, fading to a pale brown-gray or dull yellow in maturity. Under the scales, the cap surface is yellow to pale yellow-orange. While many other Suillus
species have a sticky or slimy cap, S. spraguei is dry. The flesh
is yellow.
The pores on the underside of the cap are yellowish and angular, measuring 0.5 to 5 mm (0.0196850393700787 to 0.196850393700787 in) wide, and formed by tubes that extend 4 to 8 mm (0.15748031496063 to 0.31496062992126 in) deep. These pores have a slightly decurrent
attachment to the stem (extending down its length). Young specimens have a whitish fibrous partial veil
that protects the developing pores; as the cap expands it rips the veil, which remains as a grayish ring on the stem
. The stem is 4 to 12 cm (1.6 to 4.7 in) long, and 1 to 2.5 cm (0.393700787401575 to 0.984251968503937 in) thick, roughly cylindrical in shape, or sometimes with a bulbous bottom so as to be somewhat club-shaped. The stem surface is tomentose
, with scales at the top, and a ring
on the upper half of the stem. Below the ring the stem is fibrillose, covered with a mat of soft hairs. Its color at the top is yellow, but with wine-red to reddish-brown scales below, underlaid with a pale yellow to grayish color. The stem is usually solid, rarely hollow. The tissue of all parts of the fruit body—cap, pores, and stem—will turn brownish shortly after being bruised or injured.
In deposit, such as with a spore print
, the spores
of S. spraguei appear olive-brown in color, although this changes to clay or tawny-olive after drying. Microscopically, the spores have smooth surfaces, measuring 9–11 by 3–4.5 µm
; in side profile they have asymmetrical sides and a suprahilar depression (a surface indentation formed where the spore attaches to the basidia), while in face view they appear oblong. The spores are not amyloid
, meaning that they do not absorb iodine
when stained with Melzer's reagent
. The basidia (the spore-bearing cells in the hymenium
) are thin-walled, four-spored, and have dimensions of 17–19 by 5–7.8 µm. In the presence of potassium hydroxide
, they appear hyaline
(translucent), and they become pale yellow to nearly hyaline in Melzer's reagent.
Various parts of the mushroom display characteristic color reactions to chemical tests
commonly used in mushroom identification. The cap cuticle
will turn a blackish color with the application of a drop of potassium hydroxide
(KOH), iron sulfate
(FeSO4) solution, or ammonia
solution. The mushroom flesh turns grayish-green to greenish black with a drop of FeSO4, and olive to greenish black with KOH or NH4OH.
. Its taste is not distinctive, although the odor has been described as "slightly fruity". Although it turns a blackish color when cooked, some consider it choice, and "among the better edibles in the genus Suillus." In contrast, another source on mushrooms of Québec
described the mushroom as a poor edible ("comestible médiocre"), and warned of a slightly acidic taste and disagreeable flavor. Michael Kuo's 2007 book 100 Edible Mushrooms rates the taste as mediocre, suggesting "its sluglike consistency has all the palatability of unflavored gelatin." The book recommends frying the thinly-sliced mushroom in butter or oil until it acquires a crispy texture.
), but the latter species has a darker spore print, a thicker stem, and grows in association with larch
. S. cavipes
, another associate of larch trees, is more brownish and has a hollow stalk. S. lakei
is less brightly colored than S. spraguei, has a shorter stalk, and usually grows with Douglas fir. S. decipiens
has a less intensely red cap when young, but the color of older specimens fade and can resemble S. spraguei. S. decipiens generally has a smaller stature, with a cap ranging from 4 to 7 cm (1.6 to 2.8 in) in diameter, and stem that is typically 4 – long by 0.7 – thick. Further, its pores are irregular in shape, measuring 0.5–1 mm in diameter at maturity, and stain a shade of hazel rather than reddish to brownish. It is found in the southeastern United States, from New Jersey
south to Florida
and west to Texas
.
In nature, Suillus spraguei forms ectomycorrhizal relationships with five-needled pine
species. This is a mutually beneficial relationship where the hypha
e of the fungus grow around the roots of the trees, enabling the fungus to receive moisture, protection and nutritive byproducts of the tree, and affording the tree greater access to soil nutrients. S. spraguei produces tuberculate ectomycorrhizae (covered with wart-like projections) that are described as aggregates of ectomycorrhizal roots encased in a fungal rind, and rhizomorphs that are tubular fungal cords with a hard outer sheath. The fungus has ecological host specificity, and in natural soils can only associate with white pine
, a grouping of trees classified in subgenus
Strobus of the genus Pinus. However, under controlled pure culture conditions in the laboratory, S. spraguei has also been shown to form associations with Red Pine
, Pitch Pine
, and Loblolly Pine
. Asian populations have been associated with Korean Pine
, Chinese White Pine
, Siberian Dwarf Pine
and Japanese White Pine
. In North America, fruit bodies appear earlier than most other bolete
s, as early as June (bolete fruit bodies generally begin to appear in July–September), although they may be found as late as October. Mushrooms can be parasitized
by the fungus Hypomyces completus. In the asexual
stage of H. completus, it appears initially as patches of whitish mold
on the surface of the cap or stem that rapidly spread to cover the entire mushroom surface and produce conidia (asexual spores). In the sexual
stage, the mold changes color, progressing from yellow-brown to brown, greenish-brown and eventually black as it makes perithecia, asci
-containing sexual structures that produce ascospore
s. The perithecia are pimply and give the surface a roughened texture.
A Japanese field study found that S. spraguei was the dominant fungus in a 21-year-old stand of Korean Pine, both in terms of ectomycorrhizae (measured as percentage of biomass
present in soil samples) and by fruit body production (comprising over 90% of dry weight
of total fruit bodies collected of all species). The production of S. spraguei fruit bodies averaged about one per square meter, without much variance during the four-year study period. The mushrooms appeared mostly from August to November, tended to grow in clumps, and the spatial distribution of clumps was random—the location of the clumps was not correlatable with appearances in previous years. The density of mushrooms along a forest road was higher than average, suggesting a preference for disturbed habitat. The results also suggested that S. spraguei prefers to produce fruit bodies in areas with low litter
accumulation, a finding corroborated in a later publication. This study also determined that the fungus propagates mainly by vegetative
growth (extension of underground mycelia), rather than by colonization of spores.
Suillus spraguei has a disjunct distribution
and is known from several locales in Asia, including China, Japan, Korea, and Taiwan. In North America, its range extends from eastern Canada (Nova Scotia
) south to the Carolinas, and west to Minnesota
. It has also been collected in Mexico (Coahuila
and Durango
).
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 Suillaceae
Suillaceae
The Suillaceae are a family of fungi in the order Boletales , containing the boletus-like Suillus, the small truffle-like Truncocolumella, as well as the monotypic genus Psiloboletinus. As of 2008, there are 54 species in the family...
family. It is known by a variety of common name
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...
s, including the painted slipperycap, the painted suillus or the red and yellow suillus. Suillus spraguei has had a complex taxonomical
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
history, and is also frequently referred to Suillus pictus in the literature. The readily identifiable 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...
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 dark red when fresh, dry to the touch, and covered with mats of hairs and scales that are separated by yellow cracks. On the underside of the cap are small, yellow, angular pores that become brownish as the mushroom ages. The stalk
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...
bears a grayish cottony ring
Annulus (mycology)
An annulus is the ring like structure sometimes found on the stipe of some species of mushrooms. The annulus represents the remaining part of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. An annulus may be thick and membranous, or it may be cobweb-like...
, and is typically covered with soft hairs or scales.
Suillus spraguei grows in a mycorrhizal association with several pine
Pine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
species, particularly eastern white pine
Eastern White Pine
Pinus strobus, commonly known as the eastern white pine, is a large pine native to eastern North America, occurring from Newfoundland west to Minnesota and southeastern Manitoba, and south along the Appalachian Mountains to the northern edge of Georgia.It is occasionally known as simply white pine,...
, and the fruit bodies grow on the ground, appearing from early summer to autumn. It has a disjunct distribution
Disjunct distribution
In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically...
, and is found in eastern Asia, northeastern North America, and Mexico throughout the range of the host tree. The mushroom is edible
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...
, although opinions about its quality vary. The mushroom bears a resemblance to several other Suillus
Suillus
Suillus is a genus of basidiomycete fungi in the family Suillaceae and order Boletales. Species in the genus are associated with coniferous trees, and are mostly distributed in northern temperate locations, although some species have been introduced to the Southern Hemisphere.-Taxonomy:The genus...
species, including the closely related S. decipiens
Suillus decipiens
Suillus decipiens is an edible species of mushroom in the Suillaceae family. First described by Charles Horton Peck in 1889 as Boletinus decipiens, it was transferred to Suillus in 1898 by Otto Kuntze. The fungus is found in southeastern North America, with the northern limit of its range extending...
, although the species can be differentiated by variations in color and size.
Taxonomy, phylogeny, and naming
Suillus spraguei has had a complex taxonomicTaxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
history. Although the first specimen was originally collected in New England
New England
New England is a region in the northeastern corner of the United States consisting of the six states of Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, and Connecticut...
in 1856 by Charles James Sprague, a formal scientific description
Species description
A species description or type description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species which have been described previously, or are...
was not published until 1872 when Miles Joseph Berkeley
Miles Joseph Berkeley
Miles Joseph Berkeley was an English cryptogamist and clergyman, and one of the founders of the science of plant pathology....
and Moses Ashley Curtis
Moses Ashley Curtis
Moses Ashley Curtis was a noted American botanist.Curtis was born in Stockbridge, Massachusetts and educated at Williams College in Massachusetts. After graduating, he became a tutor for the children of former Governor Edward Bishop Dudley in Wilmington, North Carolina, returning to Massachusetts...
called it Boletus spraguei. In a publication that appeared the following year, American mycologist Charles Horton Peck
Charles Horton Peck
Charles Horton Peck, born March 30, 1833 in Sand Lake, New York, died 1917 in Albany, New York, was an American mycologist of the 19th and early 20th centuries...
named the species Boletus pictus. Berkeley and Curtis had also described what they believed to be a new species—Boletus murraii—although this was later considered by 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....
to be merely a younger version of their Boletus spraguei. Although Peck's description appeared in print in 1873, the date stamp on the original publication revealed that he had sent his documents to the printer before the appearance of the 1872 Berkeley and Curtis publication, thus establishing nomenclatural priority
Principle of Priority
thumb|270px|Boa manditraIn zoology, the scientific study of animals, the Principle of Priority is one of the guiding principles of the International Code of Zoological Nomenclature, defined by Article 23....
under the rules of fungal naming. However, in 1945 Singer reported that the name Boletus pictus was illegitimate because it was a homonym
Homonym
In linguistics, a homonym is, in the strict sense, one of a group of words that often but not necessarily share the same spelling and the same pronunciation but have different meanings...
, already being used for a polypore
Polypore
Polypores are a group of tough, leathery poroid mushrooms similar to boletes, but typically lacking a distinct stalk. The technical distinction between the two types of mushrooms is that polypores do not have the spore-bearing tissue continuous along the entire underside of the mushroom. Many...
mushroom described by Carl Friedrich Schultz in 1806. The name was officially switched to Suillus spraguei in 1986 (Otto Kuntze
Otto Kuntze
Otto Carl Ernst Kuntze was a German botanist.-Biography:Otto Kuntze was born in Leipzig.An apothecary in his early career, he published an essay entitled Pocket Fauna of Leipzig. Between 1863 and...
had previously transferred the taxon to Suillus in 1898).
A 1996 molecular analysis of 38 Suillus species used the sequences of their internal transcribed spacer
Internal transcribed spacer
ITS refers to a piece of non-functional RNA situated between structural ribosomal RNAs on a common precursor transcript. Read from 5' to 3', this polycistronic rRNA precursor transcript contains the 5' external transcribed sequence , 18S rRNA, ITS1, 5.8S rRNA, ITS2, 28S rRNA and finally the 3'ETS...
s to infer phylogenetic relationships and clarify the taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
of the genus. The results indicate that S. spraguei is most closely related to S. decipiens
Suillus decipiens
Suillus decipiens is an edible species of mushroom in the Suillaceae family. First described by Charles Horton Peck in 1889 as Boletinus decipiens, it was transferred to Suillus in 1898 by Otto Kuntze. The fungus is found in southeastern North America, with the northern limit of its range extending...
. The species S. granulatus
Suillus granulatus
Suillus granulatus is a pored mushroom of the genus Suillus in the Suillaceae family. It is similar to the related S. luteus, but can be distinguished by its ringless stalk. Like S. luteus, it is an edible mushroom that often grows in a symbiosis with pine...
and S. placidus
Suillus placidus
Suillus placidus, is a species of fungus in the genus Suillus. It is an edible pored mushroom found in European and North American coniferous forests, growing in association with several species of pine of the subgenus Strobus.-Description:...
lie on a branch sister to that containing S. spraguei. These results were corroborated and extended in later publications that assessed the relationships between Asian and eastern North American isolates of various Suillus, including S. spraguei. The analysis supported the hypothesis that Chinese and U.S. S. spraguei and S. decipiens were each others' closest relatives, and the clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
that contained them could be divided into four distinct subgroups: S. decipiens, U.S. S. spraguei, China (Yunnan
Yunnan
Yunnan is a province of the People's Republic of China, located in the far southwest of the country spanning approximately and with a population of 45.7 million . The capital of the province is Kunming. The province borders Burma, Laos, and Vietnam.Yunnan is situated in a mountainous area, with...
) S. spraguei, and China (Jilin
Jilin
Jilin , is a province of the People's Republic of China located in the northeastern part of the country. Jilin borders North Korea and Russia to the east, Heilongjiang to the north, Liaoning to the south, and Inner Mongolia to the west...
) S. spraguei.
The specific epithet spraguei is an homage to the collector Sprague, while pictus means "painted" or "colored". Suillus spraguei is commonly known
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...
as the "painted slipperycap", the "painted suillus", or the "red and yellow suillus". It is also called the "eastern painted Suillus" to contrast with the "western painted Suillus" (Suillus lakei
Suillus lakei
Suillus lakei, commonly known as the matte Jack, Lake's bolete, or the western painted Suillus, is a species of fungus in the Suillaceae family. It is characterized by the distinctive reddish-brown tufted fibers or small scales on the cap, and the presence of a woolly veil on the stem...
).
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...
of the fruit body
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 3 to 12 cm (1.2 to 4.7 in) in diameter, and depending on its age, is either conic to convex, to somewhat flattened at maturity. The cap margin is initially rolled downward before straightening out, often with hanging remnants of partial veil (appendiculate). The cap surface is covered with densely matted filaments that are rough and scale-like. The scales are pink to brownish red, fading to a pale brown-gray or dull yellow in maturity. Under the scales, the cap surface is yellow to pale yellow-orange. While many other Suillus
Suillus
Suillus is a genus of basidiomycete fungi in the family Suillaceae and order Boletales. Species in the genus are associated with coniferous trees, and are mostly distributed in northern temperate locations, although some species have been introduced to the Southern Hemisphere.-Taxonomy:The genus...
species have a sticky or slimy cap, S. spraguei is dry. 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.
The pores on the underside of the cap are yellowish and angular, measuring 0.5 to 5 mm (0.0196850393700787 to 0.196850393700787 in) wide, and formed by tubes that extend 4 to 8 mm (0.15748031496063 to 0.31496062992126 in) deep. These pores have a slightly 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 (extending down its length). Young specimens have a whitish fibrous partial veil
Partial veil
thumb|150px|right|Developmental stages of [[Agaricus campestris]] showing the role and evolution of a partial veilPartial veil is a mycological term used to describe a temporary structure of tissue found on the fruiting bodies of some basidiomycete fungi, typically agarics...
that protects the developing pores; as the cap expands it rips the veil, which remains as a grayish ring on 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...
. The stem is 4 to 12 cm (1.6 to 4.7 in) long, and 1 to 2.5 cm (0.393700787401575 to 0.984251968503937 in) thick, roughly cylindrical in shape, or sometimes with a bulbous bottom so as to be somewhat club-shaped. The stem surface is tomentose
Tomentose
Tomentose is a term used to describe plant hairs that are flattened and matted, forming a woolly coating known as tomentum. Often the hairs are silver or gray-colored...
, with scales at the top, and a ring
Annulus (mycology)
An annulus is the ring like structure sometimes found on the stipe of some species of mushrooms. The annulus represents the remaining part of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. An annulus may be thick and membranous, or it may be cobweb-like...
on the upper half of the stem. Below the ring the stem is fibrillose, covered with a mat of soft hairs. Its color at the top is yellow, but with wine-red to reddish-brown scales below, underlaid with a pale yellow to grayish color. The stem is usually solid, rarely hollow. The tissue of all parts of the fruit body—cap, pores, and stem—will turn brownish shortly after being bruised or injured.
In deposit, such as with a 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...
, the spores
Basidiospore
A basidiospore is a reproductive spore produced by Basidiomycete fungi. Basidiospores typically each contain one haploid nucleus that is the product of meiosis, and they are produced by specialized fungal cells called basidia. In grills under a cap of one common species in the phylum of...
of S. spraguei appear olive-brown in color, although this changes to clay or tawny-olive after drying. Microscopically, the spores have smooth surfaces, measuring 9–11 by 3–4.5 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...
; in side profile they have asymmetrical sides and a suprahilar depression (a surface indentation formed where the spore attaches to the basidia), while in face view they appear oblong. The spores are not amyloid
Amyloid
Amyloids are insoluble fibrous protein aggregates sharing specific structural traits. Abnormal accumulation of amyloid in organs may lead to amyloidosis, and may play a role in various neurodegenerative diseases.-Definition:...
, meaning that they do not 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....
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 (the spore-bearing cells in 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 thin-walled, four-spored, and have dimensions of 17–19 by 5–7.8 µm. In the presence of potassium hydroxide
Potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...
, they appear 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 they become pale yellow to nearly hyaline in Melzer's reagent.
Various parts of the mushroom display characteristic color reactions to chemical tests
Chemical tests in mushroom identification
Chemical tests in mushroom identification are methods that aid in determining the variety of some fungi. The most useful tests are Melzer's reagent and potassium hydroxide.- Ammonia :Household ammonia can be used. A couple of drops are placed on the flesh...
commonly used in mushroom identification. 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....
will turn a blackish color with the application of a drop of potassium hydroxide
Potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...
(KOH), iron sulfate
Iron(II) sulfate
Iron sulfate or ferrous sulfate is the chemical compound with the formula FeSO4. Known since ancient times as copperas and as green vitriol, the blue-green heptahydrate is the most common form of this material...
(FeSO4) solution, or ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
solution. The mushroom flesh turns grayish-green to greenish black with a drop of FeSO4, and olive to greenish black with KOH or NH4OH.
Edibility
Suillus spraguei is an edible mushroomEdible 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...
. Its taste is not distinctive, although the odor has been described as "slightly fruity". Although it turns a blackish color when cooked, some consider it choice, and "among the better edibles in the genus Suillus." In contrast, another source on mushrooms of Québec
Quebec
Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....
described the mushroom as a poor edible ("comestible médiocre"), and warned of a slightly acidic taste and disagreeable flavor. Michael Kuo's 2007 book 100 Edible Mushrooms rates the taste as mediocre, suggesting "its sluglike consistency has all the palatability of unflavored gelatin." The book recommends frying the thinly-sliced mushroom in butter or oil until it acquires a crispy texture.
Similar species
S. spraguei is a popular edible among novice mushroom hunters as it is readily identifiable due to both its appearance and its association with White Pine. Although this distinctiveness renders it unlikely to be confused with other species, it does share similar characteristics with several other Suillus species. S. spraguei bears some resemblance to the rosy larch bolete (S. ochraceoroseusSuillus ochraceoroseus
Suillus ochraceoroseus is an edible species of mushroom in the genus Suillus.-Taxonomy:The species was first described by Wally Snell as Boletinus ochraceoroseus in 1941, based on specimens he had collected near Smith Creek in Idaho. René Pomerleau and Alexander H. Smith transferred it to...
), but the latter species has a darker spore print, a thicker stem, and grows in association with larch
Larch
Larches are conifers in the genus Larix, in the family Pinaceae. Growing from 15 to 50m tall, they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains further south...
. S. cavipes
Suillus cavipes
Suillus cavipes is an edible species of mushroom in the genus Suillus. It is found in Europe and North America....
, another associate of larch trees, is more brownish and has a hollow stalk. S. lakei
Suillus lakei
Suillus lakei, commonly known as the matte Jack, Lake's bolete, or the western painted Suillus, is a species of fungus in the Suillaceae family. It is characterized by the distinctive reddish-brown tufted fibers or small scales on the cap, and the presence of a woolly veil on the stem...
is less brightly colored than S. spraguei, has a shorter stalk, and usually grows with Douglas fir. S. decipiens
Suillus decipiens
Suillus decipiens is an edible species of mushroom in the Suillaceae family. First described by Charles Horton Peck in 1889 as Boletinus decipiens, it was transferred to Suillus in 1898 by Otto Kuntze. The fungus is found in southeastern North America, with the northern limit of its range extending...
has a less intensely red cap when young, but the color of older specimens fade and can resemble S. spraguei. S. decipiens generally has a smaller stature, with a cap ranging from 4 to 7 cm (1.6 to 2.8 in) in diameter, and stem that is typically 4 – long by 0.7 – thick. Further, its pores are irregular in shape, measuring 0.5–1 mm in diameter at maturity, and stain a shade of hazel rather than reddish to brownish. It is found in the southeastern United States, from New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
south to Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
and west to Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
.
Ecology, habitat and distribution
Pine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
species. This is a mutually beneficial relationship where 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 of the fungus grow around the roots of the trees, enabling the fungus to receive moisture, protection and nutritive byproducts of the tree, and affording the tree greater access to soil nutrients. S. spraguei produces tuberculate ectomycorrhizae (covered with wart-like projections) that are described as aggregates of ectomycorrhizal roots encased in a fungal rind, and rhizomorphs that are tubular fungal cords with a hard outer sheath. The fungus has ecological host specificity, and in natural soils can only associate with white pine
Pinus classification
There are three main subgenera of Pinus, the subgenus Strobus , the subgenus Ducampopinus , and the subgenus Pinus...
, a grouping of trees classified in subgenus
Subgenus
In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...
Strobus of the genus Pinus. However, under controlled pure culture conditions in the laboratory, S. spraguei has also been shown to form associations with Red Pine
Red Pine
Pinus resinosa, commonly known as the red pine or Norway pine, is pine native to North America. The Red Pine occurs from Newfoundland west to Manitoba, and south to Pennsylvania, with several smaller, disjunct populations occurring in the Appalachian Mountains in Virginia and West Virginia, as well...
, Pitch Pine
Pitch Pine
The Pitch Pine, Pinus rigida, is a small-to-medium sized pine, native to eastern North America. This species occasionally hybridizes with other pine species such as Loblolly Pine , Shortleaf Pine , and Pond Pine The Pitch Pine, Pinus rigida, is a small-to-medium sized (6-30 meters or 20-100 feet)...
, and Loblolly Pine
Loblolly Pine
Pinus taeda is one of several pines native to the Southeastern United States, from central Texas east to Florida, and north to Delaware. It is particularly dominant in the eastern half of North Carolina, where there are huge expanses consisting solely of Loblolly Pine trees...
. Asian populations have been associated with Korean Pine
Korean Pine
The tree species Pinus koraiensis is commonly called Korean Pine. It is native to eastern Asia, Korea, Manchuria, far eastern Russia, and central Japan. In the north of its range, it grows at moderate altitudes, typically to , whereas further south, it is a mountain tree, growing at to altitude...
, Chinese White Pine
Chinese White Pine
The Chinese White Pine is a species of pine native to China, occurring from southern Shanxi west to southern Gansu and south to Yunnan, with outlying populations in Anhui and Taiwan; it also extends a short distance into northern Myanmar. It grows at 1,000-3,300 m altitude, with the lower...
, Siberian Dwarf Pine
Siberian Dwarf Pine
Pinus pumila is a native to northeastern Asia, including the islands of Japan. This shrubby pine ranges from 1–3 m in height, exceptionally up to 5 m, but may have individual branches that extend farther along the ground in length...
and Japanese White Pine
Japanese White Pine
The Japanese White Pine is a pine in the white pine group, Pinus subgenus Strobus, native to Japan. It is also known as the Japanese Five Needle Pine ....
. In North America, fruit bodies appear earlier than most other bolete
Bolete
A bolete is a type of fungal fruiting body characterized by the presence of a pileus that is clearly differentiated from the stipe, with a spongy surface of pores on the underside of the pileus...
s, as early as June (bolete fruit bodies generally begin to appear in July–September), although they may be found as late as October. Mushrooms can be parasitized
Parasitism
Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...
by the fungus Hypomyces completus. In the asexual
Asexual reproduction
Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...
stage of H. completus, it appears initially as patches of whitish mold
Mold
Molds are fungi that grow in the form of multicellular filaments called hyphae. Molds are not considered to be microbes but microscopic fungi that grow as single cells called yeasts...
on the surface of the cap or stem that rapidly spread to cover the entire mushroom surface and produce conidia (asexual spores). In the sexual
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
stage, the mold changes color, progressing from yellow-brown to brown, greenish-brown and eventually black as it makes perithecia, asci
Ascus
An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain eight ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can number one , two, four, or multiples...
-containing sexual structures that produce ascospore
Ascospore
An ascospore is a spore contained in an ascus or that was produced inside an ascus. This kind of spore is specific to fungi classified as ascomycetes ....
s. The perithecia are pimply and give the surface a roughened texture.
A Japanese field study found that S. spraguei was the dominant fungus in a 21-year-old stand of Korean Pine, both in terms of ectomycorrhizae (measured as percentage of biomass
Biomass (ecology)
Biomass, in ecology, is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, which is the mass of one or more species, or to community biomass, which is the mass of all species in the community. It can include microorganisms,...
present in soil samples) and by fruit body production (comprising over 90% of dry weight
Dry matter
The dry matter is a measurement of the mass of something when completely dried.The dry matter of plant and animal material would be its solids, i.e. all its constituents excluding water. The dry matter of food would include carbohydrates, fats, proteins, vitamins, minerals, and antioxidants...
of total fruit bodies collected of all species). The production of S. spraguei fruit bodies averaged about one per square meter, without much variance during the four-year study period. The mushrooms appeared mostly from August to November, tended to grow in clumps, and the spatial distribution of clumps was random—the location of the clumps was not correlatable with appearances in previous years. The density of mushrooms along a forest road was higher than average, suggesting a preference for disturbed habitat. The results also suggested that S. spraguei prefers to produce fruit bodies in areas with low litter
Forest 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...
accumulation, a finding corroborated in a later publication. This study also determined that the fungus propagates mainly by vegetative
Vegetative reproduction
Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...
growth (extension of underground mycelia), rather than by colonization of spores.
Suillus spraguei has a disjunct distribution
Disjunct distribution
In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically...
and is known from several locales in Asia, including China, Japan, Korea, and Taiwan. In North America, its range extends from eastern Canada (Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
) south to the Carolinas, and west to Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
. It has also been collected in Mexico (Coahuila
Coahuila
Coahuila, formally Coahuila de Zaragoza , officially Estado Libre y Soberano de Coahuila de Zaragoza is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico...
and Durango
Durango
Durango officially Estado Libre y Soberano de Durango is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. The state is located in Northwest Mexico. With a population of 1,632,934, it has Mexico's second-lowest population density, after Baja...
).