Rubroboletus pulcherrimus

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Rubroboletus pulcherrimus
Boletus pulcherrimus 21538 ed.jpg
Rubroboletus pulcherrimus,
collected in Senguio, Michoacán, Mexico
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Boletales
Family: Boletaceae
Genus: Rubroboletus
Species:
R. pulcherrimus
Binomial name
Rubroboletus pulcherrimus
(Thiers & Halling) D.Arora, N. Siegel & J.L.Frank (2015)
Synonyms
  • Boletus pulcherrimusThiers & Halling (1976)
Rubroboletus pulcherrimus
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 Poison.pngEdibility is poisonous

Rubroboletus pulcherrimus, known as Boletus pulcherrimus until 2015, and commonly known as the red-pored bolete, [1] 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.

Contents

Taxonomy

American mycologists Harry D. Thiers and Roy E. Halling were aware of confusion on the west coast of North America over red-pored boletes; two species were traditionally recognised— Boletus satanas and Boletus eastwoodiae . However, they strongly suspected the type specimen of the latter species was in fact the former. In reviewing material they published a new name for the taxon, which Thiers had written about in local guidebooks as B. eastwoodiae, as they felt that name to be invalid. Hence in 1976 they formally described Boletus pulcherrimus, [2] from the Latin pulcherrimus, meaning "very pretty". [3] It was transferred to the genus Rubroboletus in 2015 along with several other allied reddish colored, blue-staining bolete species such as B. eastwoodiae and B. satanas. [4]

Description

Colored various shades of olive- to reddish-brown, the cap may sometimes reach 25 centimeters (10 in) in diameter and is convex in shape before flattening at maturity. The cap surface may be smooth or velvety when young, but may be scaled in older specimens; the margin of the cap is curved inwards in young specimens but rolls out and flattens as it matures. [2]

Close-up of the poroid surface Boletus pulcherrimus 8405.jpg
Close-up of the poroid surface

The cap may reach a thickness of 3 to 4 cm (1.2 to 1.6 in) when mature. [5] The adnate (attached squarely to the stem) poroid surface is bright red to dark red or red-brown and bruise dark blue or black; there are 2 to 3 pores per mm in young specimens, and in maturity they expand to about 1 or 2 per mm. [5] In cross section, the tubes and flesh are yellow. [6] The tubes are between 0.5 to 1.5 cm (0.2 to 0.6 in) long, while the angular pores are up to 1 mm in diameter; pores can range in color from dark red in young specimens to reddish brown in age. The pores will stain a blue color when cut or bruised. [2] The solid, firm stem is 7–20 cm (3–8 in) long and thick—up to 10 cm (4 in) in diameter, at the base before tapering to 2–5 cm (1–2 in) at the top. It is yellow or yellow-brown in color and bears a network of red reticulations on the upper 2/3 of its length. The spore print is olive-brown. The taste of the flesh is reportedly mild, [1] and the odor indistinct, [5] or "slightly fragrant". [7]

Microscopic characters

The spores are spindle-shaped or elliptical, thick-walled, smooth, and have dimensions of 13–16 by 5.5–6.5  μm. The basidia, the spore-bearing cells, are club-shaped (clavate), attached to 1 to 4 spores, and have dimensions of 35–90 by 9–12 μm. The cystidia (sterile, non-spore-bearing cells found interspersed among the basidia) in the hymenium have dimensions of 33–60 by 8–12 μm. Clamp connections are absent in the hyphae of B. pulcherrimus. [2]

Similar species

Although the relatively large fruiting bodies of R. pulcherrimus are distinctive, they might be confused with superficially similar species, such as Rubroboletus eastwoodiae ; the latter species has a much thicker stalk. Another similar species is R. haematinus , which may be distinguished by its yellower stem and cap colors that are various shades of brown. [8] Its darker cap and lack of reticulation on the stipe differentiate it from R. satanas. [2] Neoboletus luridiformis grow with oaks but is smaller and have non-reticulate stipe. [9]

Distribution and habitat

R. pulcherrimus has a stem that is finely netted (reticulate) Boletus pulcherrimus 8407.jpg
R. pulcherrimus has a stem that is finely netted (reticulate)

Rubroboletus pulcherrimus is found in western North America, from New Mexico and California to Washington, and may feasibly occur in British Columbia, Canada. One source notes it grows at low altitudes in the Cascade Range and Olympic Mountains; [6] another claims it grows at high elevations, over 5,000 ft (1,500 m). [7] Fruiting in autumn, it grows singly or in groups (although another source claims "never in groups") [10] in humus in mixed woodlands. [1] [11] In the original publication describing the species, Thiers and Halling note that it is associated with forests containing tanbark oaks (Lithocarpus densiflora), Douglas fir (Pseudotsuga menziesii), and Grand Fir (Abies grandis). [2] Smith and Weber mention increased fruitings after warm heavy fall rains following a humid summer. [12]

Toxicity

In general, blue-staining red-pored boletes should be avoided for consumption. [7] Thiers warned this species may be toxic after being alerted to severe gastrointestinal symptoms in one who had merely tasted it. [13] Years later, in 1994, a couple developed gastrointestinal symptoms after eating this fungus and the husband died as a result. A subsequent autopsy revealed that the man had suffered an infarction of the midgut. Rubroboletus pulcherrimus was the only bolete that had been implicated in the death of someone consuming it, [14] It is known to contain low levels of muscarine, a peripheral nervous system toxin. [15] A 2005 report from Australia recorded a fatality from muscarinic syndrome after consuming a mushroom from the genus Rubinoboletus (but possibly a species of Chalciporus ). [16]

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 violent gastroenteritis. However, reports of poisoning are rare, due to the striking coloration and unpleasant odor of the fruiting bodies, which discourage 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 bolete, 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, which are yellow when young. Other common names include the red foot bolete, dotted stemmed bolete, or dotted stem bolete.

<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, sometimes called satan's bolete, is a possibly 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>Boletus barrowsii</i> Species of fungus

Boletus barrowsii, also known in English as the white king bolete after its pale colored cap, is an edible and highly regarded fungus in the genus Boletus that inhabits western North America. Found under ponderosa pine and live oak in autumn, it was considered a color variant of the similarly edible B. edulis for many years.

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

Rubroboletus legaliae, previously known as Boletus splendidus, B. satanoides, and B. legaliae is a basidiomycete fungus of the family Boletaceae. It is poisonous, with predominantly gastrointestinal symptoms, and is related to Rubroboletus satanas.

<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 trees, suggesting a saprobic lifestyle. Despite the occasional appearances to the contrary, Aureoboletus mirabilis is mycorrhizal, and forms a close association with the tree's roots.

<i>Xerocomellus zelleri</i> Species of fungus

Xerocomellus 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.

<i>Suillellus amygdalinus</i> Species of fungus

Suillellus 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. 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 on the stipe, or by location.

<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>Rubroboletus rhodoxanthus</i> Species of fungus

Rubroboletus rhodoxanthus is a species of bolete in the family Boletaceae, native to Europe. Previously known as Boletus rhodoxanthus, it was transferred in 2014 to the newly erected genus Rubroboletus, based on DNA data.

<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 Butyriboletus 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>Tylopilus tabacinus</i> Species of fungus

Tylopilus tabacinus is a species of bolete fungus in the family Boletaceae. It is characterized by a tawny-brown cap measuring up to 17.5 cm (6.9 in) in diameter, and a reticulated stem up to 16.5 cm (6.5 in) long by 6 cm (2.4 in) thick. A characteristic microscopic feature is the distinctive crystalline substance encrusted on the hyphae in the surface of the cap. The species is known from the eastern United States from Florida north to Rhode Island, and west to Mississippi, and from eastern Mexico. It is a mycorrhizal species, and associates with oak and beech trees.

<i>Tylopilus alboater</i> Species of fungus

Tylopilus alboater, called the black velvet bolete, by some, is a bolete fungus in the family Boletaceae. The species is found in North America east of the Rocky Mountains, and in eastern Asia, including China, Japan, Taiwan, and Thailand. A mycorrhizal species, it grows solitarily, scattered, or in groups on the ground usually under deciduous trees, particularly oak, although it has been recorded from deciduous, coniferous, and mixed forests.

<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>Boletus abruptibulbus</i> Species of fungus

Boletus abruptibulbus is a species of bolete mushroom in the family Boletaceae. Described as new to science in 2009, it is found only in the Gulf Coast of the Florida Panhandle, where it grows on the ground in coastal sand dunes, one of only three North American boletes known to favor this habitat. The fruit bodies have convex brownish caps up to 8 cm (3.1 in) in diameter, supported by solid yellowish to reddish stems measuring 3–5 cm (1.2–2.0 in) long by 10–15 mm (0.4–0.6 in) thick. The pores on the underside of the cap measure about 1–2 mm in diameter and are initially pale yellow before developing a greenish tinge in age. The mushroom's spores, about 20 micrometers long, are unusually long for a member of the Boletaceae. The stem base is bulbous, a diagnostic feature for which the species is named.

<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, causing gastroenteritis if consumed.

<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>Sutorius eximius</i> Species of fungus

Sutorius eximius, commonly known as the lilac-brown bolete, is a species of fungus in the family Boletaceae. This bolete produces fruit bodies that are dark purple to chocolate brown in color with a smooth cap, a finely scaly stipe, and a reddish-brown spore print. The tiny pores on the cap underside are chocolate to violet brown. It is widely distributed, having been recorded on North America, South America, and Asia, where it grows in a mycorrhizal relationship with both coniferous and deciduous trees.

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