Xerocomus subtomentosus | |
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Scientific classification | |
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Species: | X. subtomentosus |
Binomial name | |
Xerocomus subtomentosus | |
Synonyms | |
Boletus subtomentosusL. (1753) |
Xerocomus subtomentosus | |
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Pores on hymenium | |
Cap is convex | |
Hymenium is seceding | |
Stipe is bare | |
Spore print is olive-brown | |
Ecology is mycorrhizal | |
Edibility is edible |
Xerocomus subtomentosus, commonly known as suede bolete, brown and yellow bolete , boring brown bolete or yellow-cracked bolete, is a species of bolete fungus in the family Boletaceae. The fungus was initially described by Carl Linnaeus in 1753 and known for many years as Boletus subtomentosus. It is edible, though not as highly regarded as other bolete mushrooms.
It occurs throughout Eurasia, North America and Australia and grows with a wide range of hardwood and conifer trees. It forms symbiotic ectomycorrhizal associations with living trees by enveloping the tree's underground roots with sheaths of fungal tissue. The fungus produces spore-bearing fruit bodies. The olive to tan fruit body cap is up to 10 cm (4 in) in diameter and has a distinctive velvety surface. Like other boletes, it has tubes extending downward from the underside of the cap, rather than gills; spores escape at maturity through the tube openings, or pores. The pore surface is yellow and bruises blue. The stipe, or stem, measures up to 8 cm (3 in) tall and 2 cm (0.8 in) thick.
Xerocomus subtomentosus was first described in 1753 by the father of taxonomy Carl Linnaeus as Boletus subtomentosus. [1] The starting date of fungal taxonomy had been set as January 1, 1821, to coincide with the date of the works of the 'father of mycology', Swedish naturalist Elias Magnus Fries, which meant that the name required sanction by Fries (indicated in the name by a colon) to be considered valid, as Linnaeus' work preceded this date. It was thus written Boletus subtomentosus L.:Fr. However, a 1987 revision of the International Code of Botanical Nomenclature set the starting date at May 1, 1753, the date of publication of Linnaeus' seminal work, the Species Plantarum . [2] Hence the name no longer requires the ratification of Fries' authority.
French mycologist Lucien Quélet had classified a number of Boletus species in the genus Xerocomus, with Xerocomus subtomentosus made the type species. The genus name is derived from the Ancient Greek Xeros "dry" and kome "hair", and refers to the velvety surface of the cap. [3] This classification was disputed, with many authorities not recognising the genus and continuing to use Boletus subtomentosus; however genetic analysis published in 2013 confirmed the distinctness of this species and its close relatives from the core group of fungi in the genus Boletus (sensu stricto). [4]
Xerocomus subtomentosus and relatives, including Phylloporus pelletieri , form a clade known informally as the "/Xerocomus Clade" within a larger group (informally called hypoboletus) in the suborder Boletineae. Other clades within the group include the Aureoboletus and Hemileccinum clades, as well as species currently designated Boletus (though they are not closely related to Boletus edulis ) and three species currently designated Boletellus (though they are unlikely to be close relatives of the type species, Boletellus ananas ). The clade containing the hypoboletus group and the Royoungia clade is sister to the anaxoboletus group (containing the genera Tylopilus sensu stricto, Strobilomyces , Xanthoconium , Porphyrellus , Xerocomellus , Boletus sensu stricto, and species that require new generic names (e.g., Boletus badius ) and the leccinoid group (comprising the genera Leccinellum , Leccinum , Spongiforma , and the species Retiboletus griseus ). [4] As X. subtomentosus is the type species of the genus, it and close relatives remain Xerocomus as other members are placed in different genera.
Its specific name subtomentosus is Latin "finely haired", referring to its cap. [3] Mushroom author David Arora nicknamed the mushroom the boring brown bolete from its lack of taste and appeal. [5] Other vernacular names include "yellow-cracked bolete", "suede bolete", [6] and "brown and yellow bolete". [7]
The pale olive or tan cap is initially convex before flattening, and measures 4 to 10 cm (1.6 to 3.9 in) or sometimes up to 18 cm (7.1 in) in diameter with a velvety tan surface. Occasionally the cap slits revealing yellow flesh beneath. The skin of the cap is very hard to remove. The pores underneath the cap are yellow, and bruise blue or green before fading somewhat. The stipe lacks a ring and is up to 12 cm (4.7 in) tall by 1–2 cm (0.4–0.8 in) wide. [8] The spore print is olive-brown. A drop of ammonium hydroxide on the cap instantly produces a mahogany red reaction, which distinguishes it from some other similar species of the genus. The flesh is white and has little taste or smell. [3] [5]
The rare European species Xerocomus silwoodensis , described as new to science in 2007, is similar in appearance to X. subtomentosus. It can be distinguished from the latter in the field by the darker reddish-brown tones of the cap and its preference for associating with Populus trees. [9] It has white flesh that becomes yellow-tinged on exposure to air. X. chrysonemus has bright yellow flesh and mycelium while X. ferrugineus is found only under conifers and also has yellow mycelium. [10]
Also somewhat similar are Boletus chrysenteron , B. citriniporus, and B. edulis. [8]
Xerocomus subtomentosus occurs in autumn in forests throughout Eurasia, North America and Australia and forming a mycorrhizal relationship with a wide range of hardwood and conifer trees. [3] [5] [11] It has been recorded from the vicinity of Tangier in Morocco, growing under cork oak ( Quercus suber ). [12] It is associated with bilberry and other evergreen shrubs of the heath family Ericaceae. [6] [7]
Xerocomus subtomentosus is found in subarctic areas of western Greenland, where it is common and grows in association with white birch ( Betula pubescens ). [13]
Xerocomus subtomentosus is edible, [14] although not highly regarded. Its mild taste makes it suitable for mixed mushroom dishes. [3] An elemental analysis of specimens collected from western Poland determined the mushrooms to have abundant amounts of the electrolytes potassium, phosphorus, and magnesium, with mean values of 46000, 8400, and 1100 milligramme/kilogramme dry weight, respectively, in the caps. The levels of the toxic metals cadmium, mercury, and lead in the mushrooms "did not pose a threat to a consumer's health". [15]
The Boletaceae are a family of mushroom-forming fungi, primarily characterised by small pores on the spore-bearing hymenial surface, instead of gills as are found in most agarics. Nearly as widely distributed as the agarics, the family is renowned for hosting some prime edible species highly sought after by mushroom hunters worldwide, such as the cep or king bolete . A number of rare or threatened species are also present in the family, that have become the focus of increasing conservation concerns. As a whole, the typical members of the family are commonly known as boletes.
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.
Baorangia bicolor, also known as the two-colored bolete or red and yellow bolete after its two-tone coloring scheme of red and yellow, is an edible fungus in the genus Baorangia. It inhabits most of eastern North America, primarily east of the Rocky Mountains and in season during the summer and fall months but can be found across the globe in China and Nepal. Its fruit body, the mushroom, is classed as medium or large in size, which helps distinguish it from the many similar appearing species that have a smaller stature. A deep blue/indigo bruising of the pore surface and a less dramatic bruising coloration change in the stem over a period of several minutes are identifying characteristics that distinguish it from the similar poisonous species Boletus sensibilis. There are two variations of this species, variety borealis and variety subreticulatus, and several other similar species of fungi are not poisonous.
Hortiboletus rubellus, commonly known as the ruby bolete, is a small, dainty, brightly coloured member of the family Boletaceae, with a reddish cap and stipe, and yellow pores. Like many boletes, it stains blue when cut or bruised. It is found in deciduous woodland in autumn. There is some question over its edibility, and it is reportedly of poor quality with a taste of soap. Until 2015, the species was known as Boletus rubellus.
Boletellus obscurecoccineus, known as the rhubarb bolete, is a species of fungus in the family Boletaceae, found in Australia, New Guinea, Java, Borneo, Japan, Korea, and Taiwan. It is a distinctive and colourful bolete of the forest floor.
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.
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.
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.
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.
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.
Aureoboletus russellii, commonly known as the Russell's bolete, or jagged-stemmed bolete, is a species of bolete fungus in the family Boletaceae. An edible species, it is found in Asia and eastern North America, where it grows in a mycorrhizal association with oak, hemlock, and pine trees. Fruit bodies of the fungus are characterized by their coarsely shaggy stem. The yellow-brown to reddish-brown caps are initially velvety, but become cracked into patches with age.
Xerocomus illudens is a species of bolete fungus in the family Boletaceae. Described as new to science in 1898, it is found in Asia and North America, where it grows in a mycorrhizal association with oak.
Aureoboletus projectellus is a species of bolete fungus in the family Boletaceae. Found in North America, and recently in Europe, it grows in a mycorrhizal association with pine trees.
Xerocomellus is a genus of fungi in the family Boletaceae. The genus, as it was described in 2008, contained 12 species. However X. rubellus and X. engelii were transferred to the new genus Hortiboletus and X. armeniacus was transferred to the new genus Rheubarbariboletus in 2015. Molecular analysis supports the distinction of Xerocomellus species from Boletus and Xerocomus, within which these species were formerly contained. Xerocomellus in fact is only distantly related to Xerocomus and is most closely related to Tylopilus, Boletus sensu stricto, Porphyrellus, Strobilomyces, and Xanthoconium.
Imperator torosus, commonly known as the brawny bolete, is a species of bolete fungus in the family Boletaceae. It is native to southern Europe east to the Caucasus and Israel. It is generally associated with deciduous trees such as hornbeam, oak and beech in warm, dry locales. Although generally rare in Europe, it appears to be relatively common in Hungary. Appearing in summer and autumn on chalky soils, the stocky fruit bodies have an ochre cap up to 20 cm (8 in) across, yellow pores on the cap underside, and a wine-red to brown or blackish stipe up to 6–15 cm (2.4–5.9 in) long by 3–6 cm (1.2–2.4 in) wide. The pale yellow flesh changes to different colours when broken or bruised depending on age; younger mushrooms become reddish, and older ones additionally take on bluish tones.
Imperator luteocupreus is a species of bolete fungus in the family Boletaceae. It is native to southern Europe, where it is found under chestnut (Castanea) and oak (Quercus). Although it was originally described in genus Boletus, it was placed in the new genus Imperator in 2015, based on phylogenetic inferences.
Buchwaldoboletus lignicola is a species of bolete fungus in the family Boletaceae native to Europe and North America. Found on wood, it is actually parasitic on the fungus Phaeolus schweinitzii. It has a convex yellow- to rusty brown cap, yellow to yellow-brown pores and stipe, and a brown spore print. Its edibility is unknown.
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.
Hemileccinum impolitum is a basidiomycete fungus of the family Boletaceae, native to Europe. It is commonly referred to as the iodine bolete, because its fruit bodies tend to emit an iodine-like odour when cut, more detectable in the stem base or overripe specimens.
Imleria badia, commonly known as the bay bolete, is an edible, pored mushroom found in Eurasia and North America, where it grows in coniferous or mixed woods on the ground or on decaying tree stumps, sometimes in prolific numbers. Both the common and scientific names refer to the bay- or chestnut-coloured cap, which is almost spherical in young specimens before broadening and flattening out to a diameter up to 15 cm (6 in). On the cap underside are small yellowish pores that turn dull blue-grey when bruised. The smooth, cylindrical stipe, measuring 4–9 cm long by 1–2 cm thick, is coloured like the cap, but paler. Some varieties have been described from eastern North America, differing from the main type in both macroscopic and microscopic morphology.