Suillellus amygdalinus

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Suillellus amygdalinus
Suillellus amygdalinus Baja.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Boletales
Family: Boletaceae
Genus: Suillellus
Species:
S. amygdalinus
Binomial name
Suillellus amygdalinus
(Thiers) Vizzini, Simonini & Gelardi (2014)
Synonyms [1]
  • Boletus puniceusThiers (1965)
  • Boletus amygdalinusThiers (1975)
Suillellus amygdalinus
Information icon.svg
Pores icon.pngPores on hymenium
Convex cap icon.svg Cap is convex
Adnate gills icon2.svg Hymenium is adnate
Bare stipe icon.svg Stipe is bare
Transparent spore print icon.svg
Spore print is olive-brown
Mycorrhizal fungus.svgEcology is mycorrhizal
Mycomorphbox Question.pngEdibility is unknown

Suillellus amygdalinus (formerly Boletus amygdalinus) is a fungus of the bolete family found in western North America. The fruit bodies, or mushrooms, are characterized by their thick, red to brown caps, red pores, and the strong bluing reaction observed when the mushroom tissue is injured or cut. The cap can reach diameters of up to 12 cm (4.7 in) and the stipe 9 cm (3.5 in) long by 3 cm (1.2 in) thick at maturity. This mushroom has been found in manzanita and madrone woodlands of central California north to southern Oregon. Although the edibility of the mushroom is not known with certainty, it may be poisonous, and is not recommended for consumption. [2] Other similar red-pored, bluing boletes from North America, including Rubroboletus eastwoodiae , Boletus luridiformis , and B. subvelutipes , can be distinguished from S. amygdalinus either by the color of the cap, the degree of reticulation (a network of raised ridges) on the stipe, or by location.

Contents

Taxonomy

The species was first named Boletus puniceus by Harry D. Thiers in 1965, based on specimens he found in Napa County, California, on 23 November 1963. [3] In 1975, Thiers changed the name to Boletus amygdalinus (a nomen nudum ) as he discovered that the epithet had already been used for a different bolete found in Yunnan, China, [2] published in 1948. [4] The fungus was transferred to Suillellus in 2014 [5] after molecular phylogenetics demonstrated that S. amygdalinus was in a lineage distinct from Boletus. [6]

In Latin, amygdaline means relating to or resembling an almond. [7]

Description

Boletus amygdalinus 79355.jpg
The stipe is not reticulate.
Boletus amygdalinus 63513.jpg
A collection from Forestville, California

Suillellus amygdalinus is a large solid mushroom with a convex to somewhat flattened, irregular cap that can reach diameters of 6 to 12 cm (2.4 to 4.7 in) at maturity. [8] The surface of the cap is dry, and matted with fibers; the cap color of young specimens is red, but the mushrooms typically change to more brownish tones as they mature. The margin of the cap starts out curved inwards (incurved) and gradually becomes curved downwards (decurved) with age. The pores on the underside of the cap are 0.5 to 1 mm (0.02 to 0.04 in) wide, angular, and red or red-orange, while the tubes are 1 to 1.5 cm (0.4 to 0.6 in) deep. [3]

The stipe lacks a netted pattern (reticulation) and is yellow in color but is often covered by red hairs, especially near the base. The stipe is either equal in width throughout, or thicker in the middle; it reaches dimensions of 4–9 cm (1.6–3.5 in) long by 1–3 cm (0.4–1.2 in) thick. [8] The base of the stipe is typically bent. [3] The flesh is 1 to 2 cm (0.4 to 0.8 in) thick, and yellow in color, but like all parts of the mushroom, will stain blue immediately upon bruising or cutting. [2] Both the odor and taste of the fruit bodies are mild. [9]

Although the edibility of S. amygdalinus is not known with certainty, authorities often recommend to avoid consuming blue-staining, red-pored boletes, as several are poisonous. [2] [10] The species was implicated in one group of poisonings in California in 1996–97, but because of the nature of the symptoms experienced, there was probably more than one type of mushroom consumed. [11]

Microscopic characteristics

The thick-walled ellipsoid spores contain vacuoles. Boletus amygdalinus 69306.jpg
The thick-walled ellipsoid spores contain vacuoles.

Suillellus amygdalinus produces a dark olive-brown spore print. The spores are thick-walled, smooth, and ellipsoid to somewhat spindle-shaped, with dimensions of 11.2–16 by 5.2–8  µm. They become dark ochraceous when stained with Melzer's reagent, and, because of the occasional presence of two large vacuoles, may appear as if they are two-celled. The basidia (the spore-bearing cells) are club-shaped, contain numerous vacuoles, and measure 30–35 by 9–11 µm. Cystidia are present on sides of the tubes, and they measure 45–54 by 10–12 µm. Clamp connections are not present in the hyphae of S. amygdalinus. [3]

Various chemical color tests can be used to help identify fruit bodies suspected to be S. amygdalinus. A drop of dilute potassium hydroxide (KOH) will turn the cap flesh dingy orange, while it turns the cap cuticle red, or darker. Ammonia (as ammonium hydroxide, NH4OH) produces a dingy yellow on the flesh, and brown on the cap. Iron sulphate (FeSO4) produces either no change to a pale grey color with both the flesh and the cuticle. Hydrochloric acid (HCl) causes the flesh to turn orange or pink, but has no color reaction with the cuticle. [3] [12]

Similar species

Bolete lookalikes
Boletus erythropus1.jpg
Boletus luridiformis
Boletus satanas.JPG
Rubroboletus satanas
Boletus subvelutipes 53895.jpg
Boletus subvelutipes

There are several other red-pored, bluing boletes that could be confused with S. amygdalinus. The poisonous European species Rubroboletus satanas and its North American counterpart R. eastwoodiae have lighter colored caps and a reticulate pattern on the stipe. [13] B. subvelutipes is a highly variable species from eastern North America that includes red in its range of cap colors, and has a fuzzy coating of hairs near the base of its stipe; it may represent a group of species. [14] Another similar species is B. luridiformis , found in North America and Northern Europe under both broadleaf trees and conifers. Unlike S. amygdalinus, however, B. luridiformis has a dark brown to nearly blackish-brown cap, and a yellow stipe with a dense covering of red pruina (dots). [15] B. frostii is also similar. [8]

Distribution and habitat

Suillellus amygdalinus mushrooms grow on the ground in groups, or scattered about. The fungus has been reported from low-elevation hardwood forests composed of live oak, manzanita and madrone in California, [9] and Oregon. Fruiting occurs after the onset of autumn rains, usually between the October and January. [15] The mushroom can be difficult to spot, as its cap is similar in coloring to the leaves of the madrone tree with which it is associated, and because the mushroom is frequently buried under leaves. [2]

See also

Related Research Articles

<i>Rubroboletus satanas</i> Species of fungus

Rubroboletus satanas, commonly known as Satan's bolete or the Devil's bolete, is a basidiomycete fungus of the bolete family (Boletaceae) and one of its most infamous members. It was known as Boletus satanas before its transfer to the new genus Rubroboletus in 2014, based on molecular phylogenetic data. Found in broad-leaved and mixed woodland in the warmer regions of Europe, it is classified as a poisonous mushroom, known to cause gastrointestinal symptoms of diarrhea and violent vomiting. However, reports of poisoning are rare, due to its striking appearance and at times putrid smell, which discourage casual experimentation.

<i>Caloboletus calopus</i> Species of fungus in the family Boletaceae found in Asia, Northern Europe and North America

Caloboletus calopus, commonly known as the bitter beech bolete or scarlet-stemmed bolete, is a fungus of the bolete family, found in Asia, Northern Europe and North America. Appearing in coniferous and deciduous woodland in summer and autumn, the stout fruit bodies are attractively coloured, with a beige to olive cap up to 15 cm (6 in) across, yellow pores, and a reddish stipe up to 15 cm (6 in) long and 5 cm (2 in) wide. The pale yellow flesh stains blue when broken or bruised.

<i>Neoboletus luridiformis</i> Species of fungus

Neoboletus luridiformis, also previously known as Boletus luridiformis and (invalidly) as Boletus erythropus, is a fungus of the bolete family, all of which produce mushrooms with tubes and pores beneath their caps. It is found in Northern Europe and North America, and is commonly known as the scarletina bolete, for its red pores. Other common names is: red foot bolete, dotted stemmed bolete, dotted stem bolete.

<i>Rubroboletus pulcherrimus</i> Species of mushroom

Rubroboletus pulcherrimus—known as Boletus pulcherrimus until 2015—is a species of mushroom in the family Boletaceae. It is a large bolete from Western North America with distinguishing features that include a netted surface on the stem, a red to brown cap and stem color, and red pores that stain blue upon injury. Until 2005 this was the only bolete that has been implicated in the death of someone consuming it; a couple developed gastrointestinal symptoms in 1994 after eating this fungus with the husband succumbing. Autopsy revealed infarction of the midgut.

<i>Suillellus luridus</i> Species of edible fungus of the bolete family, found in Asia, Europe, and eastern North America

Suillellus luridus, commonly known as the lurid bolete, is a fungus of the family Boletaceae, found in calcareous broadleaved woodlands in Europe. Fruit bodies appear in summer and autumn and may be locally abundant. It is a firm bolete with an olive-brown cap up to 20 cm (8 in) in diameter, with small orange or red pores on the underside. The stout ochre stem reaches 8–14 cm (3–6 in) high and 1–3 cm (0.4–1.2 in) wide, and is patterned with a red network. Like several other red-pored boletes, it stains blue when bruised or cut.

<i>Rubroboletus eastwoodiae</i> Species of fungus

Rubroboletus eastwoodiae, or satan's bolete, is a toxic basidiomycete fungus of the bolete family. It occurs on the West Coast of the United States. It is closely related to Rubroboletus pulcherrimus.

<i>Exsudoporus frostii</i> Species of fungus in the family Boletaceae found in North America

Exsudoporus frostii, commonly known as Frost's bolete or the apple bolete, is a bolete fungus first described scientifically in 1874. A member of the family Boletaceae, the mushrooms produced by the fungus have tubes and pores instead of gills on the underside of their caps. Exsudoporus frostii is distributed in the eastern United States from Maine to Georgia, and in the southwest from Arizona extending south to Mexico and Costa Rica. A mycorrhizal species, its fruit bodies are typically found growing near hardwood trees, especially oak.

<i>Butyriboletus appendiculatus</i> Species of fungus

Butyriboletus appendiculatus is an edible pored mushroom that grows under oaks and other broad leaved trees such as beech. It is commonly known as the butter bolete. It often grows in large colonies beneath the oak trees, and is frequently found cohabiting with old oaks in ancient woodland. It is relatively rare in Britain. Its stipe and pores are often bright yellow and its flesh stains bright blue when cut or bruised.

<i>Aureoboletus mirabilis</i> Species of fungus

Aureoboletus mirabilis, commonly known as the admirable bolete, the bragger's bolete, and the velvet top, is an edible species of fungus in the Boletaceae mushroom family. The fruit body has several characteristics with which it may be identified: a dark reddish-brown cap; yellow to greenish-yellow pores on the undersurface of the cap; and a reddish-brown stem with long narrow reticulations. Aureoboletus mirabilis is found in coniferous forests along the Pacific Coast of North America, and in Asia. Unusual for boletes, A. mirabilis sometimes appears to fruit on the wood or woody debris of Hemlock, suggesting a saprobic lifestyle. Despite occasional appearances to the contrary, Aureoboletus mirabilis is mycorrhizal, and forms close mutualistic associations with hemlock roots.

<i>Leccinum manzanitae</i> Species of fungus

Leccinum manzanitae is an edible species of bolete fungus in the family Boletaceae. Described as new to science in 1971, it is commonly known as the manzanita bolete for its usual mycorrhizal association with manzanita trees. Its fruit bodies (mushrooms) have sticky reddish to brown caps up to 20 cm (8 in), and its stipes are up to 16 cm (6.3 in) long and 3.5 cm (1.4 in) thick. They have a whitish background color punctuated with small black scales known as scabers. Found only in the Pacific Northwest region of the United States and Canada, it is the most common Leccinum species in California. The mushroom is edible, although opinions vary as to its quality. L. manzanitae can be usually distinguished from other similar bolete mushrooms by its large size, reddish cap, dark scabers on a whitish stipe, and association with manzanita and madrone.

<i>Suillus brevipes</i> Species of edible fungus in the family Suillaceae found throughout North America

Suillus brevipes is a species of fungus in the family Suillaceae. First described by American mycologists in the late 19th century, it is commonly known as the stubby-stalk or the short-stemmed slippery Jack. The fruit bodies (mushrooms) produced by the fungus are characterized by a chocolate to reddish-brown cap covered with a sticky layer of slime, and a short whitish stipe that has neither a partial veil nor prominent, colored glandular dots. The cap can reach a diameter of about 10 cm, while the stipe is up to 6 cm long and 2 cm thick. Like other bolete mushrooms, S. brevipes produces spores in a vertically arranged layer of spongy tubes with openings that form a layer of small yellowish pores on the underside of the cap.

<i>Caloboletus rubripes</i> Species of fungus

Caloboletus rubripes, commonly known as the red-stipe bolete or the red-stemmed bitter bolete, is a mushroom in the family Boletaceae. It was known as Boletus rubripes until 2014. Fruit bodies (mushrooms) are robust, with caps up to 18 cm in diameter, atop thick stipes 5–12 cm long. Mushrooms are non-toxic, but is so bitter as to be inedible. The mushroom flesh has a very strong bluing reaction when cut or damaged. and forms mycorrhizal relationships, primarily with conifers. It can be differentiated from similar boletes by its cap color and non-reticulate stipe.

<i>Suillus pungens</i> Species of fungus in the family Suillaceae found in California

Suillus pungens, commonly known as the pungent slippery jack or the pungent suillus, is a species of fungus in the genus Suillus. The fruit bodies of the fungus have slimy convex caps up to 14 cm (5.5 in) wide. The mushroom is characterized by the very distinct color changes that occur in the cap throughout development. Typically, the young cap is whitish, later becoming grayish-olive to reddish-brown or a mottled combination of these colors. The mushroom has a dotted stem (stipe) up to 7 cm (2.8 in) long, and 2 cm (0.8 in) thick. On the underside on the cap is the spore-bearing tissue consisting of minute vertically arranged tubes that appear as a surface of angular, yellowish pores. The presence of milky droplets on the pore surface of young individuals, especially in humid environments, is a characteristic feature of this species. S. pungens can usually be distinguished from other similar Suillus species by differences in distribution, odor and taste. The mushroom is considered edible, but not highly regarded.

<i>Butyriboletus regius</i> Species of fungus

Butyriboletus regius, commonly known as the royal bolete or red-capped butter bolete, is a basidiomycete fungus of the genus Boletus found in China and Europe. B. regius has a pink cap, yellow flesh, and a reticulate pattern on the stem. Harry D. Thiers described a similar mushroom from California as B. regius, though it is not the same species. B. regius in Europe does not stain when exposed to air, or stains weakly, but the California species stains blue. Both European and California species are considered choice edibles.

<i>Boletus rubroflammeus</i> Species of fungus

Boletus rubroflammeus is a species of bolete fungus in the family Boletaceae. First described from Michigan in 1971, it is found in the eastern United States and Mexico, where it grows in a mycorrhizal association with hardwood trees. The fruit bodies (mushrooms) of the fungus have caps that are deep red to purplish red, and dark red pores. The stem has coarse, dark red reticulations and a narrow yellow area at the top. All parts of the mushroom quickly stain blue when injured or cut. Lookalikes include Boletus flammans, a lighter-colored species that grows with conifers. Other similar species can be distinguished by differences in distribution, morphology, staining reaction, and microscopic characteristics. Boletus rubroflammeus mushrooms are poisonous, and can cause gastrointestinal distress if consumed.

<i>Aureoboletus auriflammeus</i> Species of fungus

Aureoboletus auriflammeus, commonly known as the flaming gold bolete, is a species of bolete fungus in the family Boletaceae. Described as new to science in 1872, it is found in eastern North America, where it grows in a mycorrhizal association with oaks. The caps of the fruit bodies are golden orange, with a yellow pore surface on the underside, and a reticulated (network-like) stem. The edibility of the mushroom is not known.

<i>Boletus subvelutipes</i> Species of fungus

Boletus subvelutipes, commonly known as the red-mouth bolete, is a bolete fungus in the family Boletaceae. It is found in Asia and North America, where it fruits on the ground in a mycorrhizal association with both deciduous and coniferous trees. Its fruit bodies (mushrooms) have a brown to reddish-brown cap, bright yellow cap flesh, and a stem covered by furfuraceous to punctate ornamentation and dark red hairs at the base. Its flesh instantly stains blue when cut, but slowly fades to white. The fruit bodies are poisonous, and produce symptoms of gastrointestinal distress if consumed.

<i>Harrya chromapes</i> Species of fungus

Harrya chromapes, commonly known as the yellowfoot bolete or the chrome-footed bolete, is a species of bolete fungus in the family Boletaceae. The bolete is found in eastern North America, Costa Rica, and eastern Asia, where it grows on the ground, in a mycorrhizal association with deciduous and coniferous trees. Fruit bodies have smooth, rose-pink caps that are initially convex before flattening out. The pores on the cap undersurface are white, aging to a pale pink as the spores mature. The thick stipe has fine pink or reddish dots (scabers), and is white to pinkish but with a bright yellow base. The mushrooms are edible but are popular with insects, and so they are often infested with maggots.

<i>Boletus subluridellus</i> Species of fungus

Boletus subluridellus is a species of bolete fungus in the family Boletaceae. Described as new to science in 1971 by American mycologists, the bolete is found in the eastern United States and Canada. It grows on the ground in coniferous and mixed forests in a mycorrhizal association with deciduous trees, especially oak. The fruit bodies (mushrooms) have orangish-red, broadly convex caps that are up to 10 cm (3.9 in) in diameter, with small, dark reddish pores on the underside. The pale yellow stipe measures 4–9 cm (1.6–3.5 in) long by 1.5–2.3 cm (0.6–0.9 in) thick. All parts of the fruit body will quickly stain blue when injured or touched.

<i>Rubroboletus</i> Genus of fungi

Rubroboletus is a genus of bolete fungi in the family Boletaceae. It was circumscribed by Chinese mycologists in 2014 with Rubroboletus sinicus as the type species. Species are characterized by having a reddish cap surface, yellow tubes on the underside of the cap, and an orange-red to blood-red pore surface. Pinkish to red spots (reticula) are present on the stipe surface, and a bluish color change occurs when the bolete flesh is injured. Rubroboletus mushrooms have an olive-brown spore print, and produce smooth spores. Eight species were included in the original circumscription ; five were added in 2015, and another in 2017.

References

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