Rubroboletus rhodoxanthus

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Rubroboletus rhodoxanthus
Boletus rhodoxanthus.JPG
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Boletales
Family: Boletaceae
Genus: Rubroboletus
Species:
R. rhodoxanthus
Binomial name
Rubroboletus rhodoxanthus
(Krombh.) Kuan Zhao & Zhu L.Yang (2014)
Synonyms
  • Boletus sanguineusvar.rhodoxanthusKrombh. (1836)
  • Boletus rhodoxanthus(Krombh.) Kallenb. (1925)
  • Boletus rhodopurpureusvar.rhodoxanthus(Krombh.) Bon (1985)
  • Suillellus rhodoxanthus(Krombh.) Blanco-Dios (2015)
Rubroboletus rhodoxanthus
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 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.

Contents

It produces large, colourful fruit bodies with pink patches on the cap, red pores in the hymenial surface and has a robust stem decorated in a dense, red-coloured network pattern. When longitudinally sliced, its flesh is distinctly bright yellow in the stem and discolours blue only in the cap, an excellent diagnostic feature distinguishing it from similar species.

The fungus is more widespread in warm broad-leaved forests of southern Europe, where it grows in mycorrhizal symbiosis with trees of the family Fagaceae, particularly oak ( Quercus ) and beech ( Fagus ). However, it is rare in northern regions and regarded as critically endangered or extinct in some countries.

Rubroboletus rhodoxanthus is generally regarded as inedible and may cause adverse gastrointestinal symptoms if consumed.

Taxonomy and phylogeny

The fungus was first described in 1836 by Czech mycologist Julius Vincenz von Krombholz, who considered it to be a variety of Boletus sanguineus. [1] In 1925, it was recombined as a distinct species by German mycologist Franz Joseph Kallenbach, [2] and the fungus remained in genus Boletus until 2014. The species epithet is derived from the Ancient Greek words ρόδο (rhódo, "rose" or "pink") and ξανθός (xanthós, "blonde" or "fair").

The first extensive phylogenetic studies on Boletaceae in 2006 [3] and 2013, [4] indicated that Boletus was not monophyletic and hence an artificial arrangement. A 2014 study by Wu and colleagues recognised 22 generic clades within Boletaceae, concluding that Boletus dupainii and some closely related red-pored species belong to a distinct clade, distant from the core clade of Boletus (comprising Boletus edulis and allied taxa). [5] The new genus Rubroboletus was therefore described to accommodate species in this clade and B. rhodoxanthus was transferred to this genus. [6] The placement of the species in genus Suillellus , following an online recombination by Blanco-Dios, [7] was not supported by molecular data and has been subsequently rejected by later authors. [8] [9] [10] [11]

Description

The cap is at first hemispherical, gradually becoming convex to almost flat as the fungus expands, with a diameter of 10 to 20 cm (4 to 8 in), but can sometimes grow up to 30 cm (12 in). It is at first slightly velvety and coloured mostly whitish-grey, but soon becomes smooth, pinkish-grey, pinkish-beige or pinkish-red, especially towards the margin or when handled. [12] [13] [14]

The tubes are adnate to emarginate, 0.5 to 1.5 cm (0 to 0.5 in) long and initially yellow, becoming somewhat olivaceous-yellow in very mature fruit bodies and staining blue when cut. The pores (tube mouths) are orange to deep red and instantly bluing when handled. [15] [16]

The stem is 8 to 12 cm (3 to 4.5 in) long by 3 to 6 cm (1 to 2.5 in) wide, bulbous or clavate when young, becoming more elongated and cylindrical at maturity. It is orange or orange-yellow at the top (apex), gradually becoming orange-red to carmine-red in the lower part and bears a dense, orange-red to carmine-red reticulation (network pattern). [17] [18]

Sectioned fruit body displaying the characteristic yellow flesh and bluing in the cap. 2015-06-21 Rubroboletus rhodoxanthus (Krombh.) Kuan Zhao et Zhu L. Yang 530218.jpg
Sectioned fruit body displaying the characteristic yellow flesh and bluing in the cap.

The flesh is distinctly bright yellow and unchanging in the stem, but paler and turning blue when cut only in the cap. It has a mild taste. [19]

The spores are olive-brown in mass. When viewed under the microscope they are ellipsoid to fusiform (spindle-shaped), measuring 10–15.5 by 4–5.5  μm. The cap cuticle is a trichodermium of septate cylindrical hyphae, sometimes finely incrusted. [13] [20]


Similar species

Distribution and habitat

Regarded as a rare species in northern Europe, Rubroboletus rhodoxanthus is more frequently encountered in warm, southern regions. It forms ectomycorrhizal associations with members of the Fagaceae, particularly oak ( Quercus ) and beech ( Fagus ), but sometimes also with chestnut ( Castanea ). [20] [15] Molecular phylogenetic testing has confirmed its presence in France, [11] Italy, [6] Portugal [21] and the islands of Cyprus [11] and Sardinia, [6] but it is probably widespread throughout most of the Mediterranean region. [17] [20]

It has been reported as locally frequent on the island of Cyprus, where it appears in seasons with early rainfall, growing on serpentine soil under the endemic golden oak ( Quercus alnifolia ). [22] In contrast, it is considered critically endangered in the Czech Republic [23] and reported as extinct in England. [18] In the British Islands it known only from Northern Ireland. [19]

Toxicity

Rubroboletus rhodoxanthus is generally regarded as inedible [13] or even poisonous, [24] [18] [10] and can cause an adverse gastrointestinal reaction if eaten. In the Colour Atlas of Poisonous Fungi, [25] Bresinsky and Besl claim that the fungus might be edible if thoroughly cooked, but warn against collecting it because of its rarity and possibility of confusion with R. satanas .

Related Research Articles

<span class="mw-page-title-main">Boletaceae</span> Family of fungi

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.

<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>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>Baorangia bicolor</i> Edible fungus in the genus Baorangia

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.

<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>Hortiboletus rubellus</i> Species of fungus

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.

<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>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>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>Imperator rhodopurpureus</i> Species of fungus

Oldrose bolete, Imperator rhodopurpureus, is an inedible fungus of the genus Imperator, found under deciduous trees including oak and beech in neutral soils. Initially described as Boletus rhodopurpureus, it was transferred to the new genus Imperator in 2015. The bolete is considered critically endangered in the Czech Republic., and endangered in the United Kingdom, reported most commonly from Berkshire and Hampshire, and typically very rare throughout, although up to a hundred fruiting bodies have been recorded at a few sites.

<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>Rubroboletus rubrosanguineus</i> Species of fungus

Rubroboletus rubrosanguineus is a species of bolete fungus in the family Boletaceae that is found in Europe.

<i>Imperator luteocupreus</i> Species of fungus

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.

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

Rubroboletus dupainii, commonly known as Dupain's bolete, is a bolete fungus of the genus Rubroboletus. It is native to Europe, where it is threatened, and red listed in six countries. It also occurs in North America, although it is rare there. It was first recorded from North Carolina, and then from Iowa in 2009. It was reported from Belize in 2007, growing under Quercus peduncularis and other oaks.

<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.

Rubroboletus pulchrotinctus is a rare bolete fungus in the genus Rubroboletus, native to central and southern Europe. It was originally described in genus Boletus by Italian mycologist Carlo Luciano Alessio in 1985, but subsequently transferred to genus Rubroboletus by Zhao and colleagues (2015), on the basis of molecular evidence. Phylogenetically, R. pulchrotinctus is the sister-species of the better known Rubroboletus satanas, with which it shares several morphological features.

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

Rubroboletus lupinus, commonly known as the wolf bolete, is a bolete fungus of the genus Rubroboletus. Originally described by Elias Magnus Fries in 1838 as species of Boletus, it was transferred to Rubroboletus in 2015, a genus circumscribed to host other allied reddish-colored, blue-staining bolete species forming a distinct clade. The species epithet is derived from the Latin word lupus, meaning "wolf".

<i>Hemileccinum impolitum</i> Species of fungus

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 odour when cut, more detectable in the stem base or overripe specimens.

<i>Leccinellum lepidum</i> Species of fungus

Leccinellum lepidum is a species of bolete in the family Boletaceae. Originally described as Boletus lepidus in 1965, the fungus has gone through controversial taxonomic treatments over the years and was subsequently transferred to genus Krombholziella in 1985, to genus Leccinum in 1990, and to genus Leccinellum in 2003. It is the sister-species of Leccinellum corsicum, with which it had been erroneously synonymised by some authors in the past.

References

  1. ↑ Krombholz JV von. (1836). Naturgetreue Abbildungen und Beschreibungen der Schwämme. 5: 1-17
  2. ↑ Kallenbach FJ. (1925). Z. Pilzk. 5(1): 24
  3. ↑ Binder M, Hibbett DS. (2006). "Molecular systematics and biological diversification of Boletales". Mycologia. 98 (6): 971–981. doi:10.1080/15572536.2006.11832626. PMID   17486973. S2CID   10575874.
  4. ↑ Nuhn ME, Binder M, Taylor AFS, Halling RE, Hibbett DS (2013). "Phylogenetic overview of the Boletineae". Fungal Biology. 117 (7–8): 479–511. doi:10.1016/j.funbio.2013.04.008. PMID   23931115.
  5. ↑ Wu G, Feng B, Xu J, Zhu XT, Li YC, Zeng NK, Hosen MI, Yang ZL (2014). "Molecular phylogenetic analyses redefine seven major clades and reveal 22 new generic clades in the fungal family Boletaceae". Fungal Diversity. 69 (1): 93–115. doi:10.1007/s13225-014-0283-8. S2CID   15652037.
  6. 1 2 3 Zhao K, Wu G, Yang ZL (2014). "A new genus, Rubroboletus, to accommodate Boletus sinicus and its allies". Phytotaxa. 188 (2): 61–77. doi:10.11646/phytotaxa.188.2.1.
  7. ↑ Blanco-Dios JB. (2015). Nomenclatural novelties. Index Fungorum. 211: 1-2
  8. ↑ Wu G, Li YC, Zhu XT, Zhao K, Han LH, Cui YY, Li F, Xu J, Yang ZL. (2016). One hundred noteworthy boletes from China. Fungal Diversity 81(1): 25–188.
  9. ↑ Tibpromma S, et al. (2017). "Fungal diversity notes 491–602: taxonomic and phylogenetic contributions to fungal taxa" (PDF). Fungal Diversity. 83 (1): 1–261. doi:10.1007/s13225-017-0378-0. S2CID   207464240.
  10. 1 2 Zhao K, Shao HM (2017). "A new edible bolete, Rubroboletus esculentus, from southwestern China". Phytotaxa. 303 (3): 243–52. doi:10.11646/phytotaxa.303.3.4.
  11. 1 2 3 Loizides M, Bellanger JM, Assyov B, Moreau PA, Richard F (2019). "Present status and future of boletoid fungi (Boletaceae) on the island of Cyprus: cryptic and threatened diversity unraveled by 10-year study". Fungal Ecology. 41 (13): 65–81. doi:10.1016/j.funeco.2019.03.008.
  12. ↑ Ellis MB, Ellis JP (1990). Fungi without gills (hymenomycetes and gasteromycetes): an identification handbook. Springer.
  13. 1 2 3 Breitenbach J, Kränzlin F (1991). Pilze der Schweiz 3(1). Röhrlinge und Blätterpilze (in German). Luzern, Switzerland: Verlag Mykologia. ISBN   978-3-85604-030-7.
  14. ↑ Garnweidner E. (1994). Mushrooms and Toadstools of Britain and Europe. Collins.
  15. 1 2 Galli R. (2007). I Boleti. Atlante pratico-monographico per la determinazione dei boleti (in Italian) (3rd ed.). Milano, Italy: Dalla Natura.
  16. ↑ Loizides M, Kyriakou T, Tziakouris A (2011). Edible & toxic fungi of Cyprus (in Greek and English). Published by the authors. pp. 128–129. ISBN   978-9963-7380-0-7.
  17. 1 2 Courtecuisse R, Duhem B (1995). Mushrooms & Toadstools of Britain & Europe. London, UK: Harper-Collins.
  18. 1 2 3 Phillips R. (2006). Mushrooms. Pan MacMillan. ISBN   0-330-44237-6.
  19. 1 2 Kibby G (2016). British Boletes: with key to species (7th ed.).
  20. 1 2 3 Muñoz JA. (2005). Fungi Europaei 2: Boletus s.l. Italy: Edizioni Candusso. ISBN   978-88-901057-6-0.
  21. ↑ Martin MP, Raidl S (2002). "The taxonomic position of Rhizopogon melanogastroides (Boletales)". Mycotaxon. 84: 221–228.
  22. ↑ Loizides M (2011). "Quercus alnifolia: The indigenous golden oak of Cyprus and its fungi". Field Mycology. 12 (3): 81–88. doi: 10.1016/j.fldmyc.2011.06.004 .
  23. ↑ Mikšik M. (2012). "Rare and protected species of boletes of the Czech Republic". Field Mycology. 13 (1): 8–16. doi: 10.1016/j.fldmyc.2011.12.003 .
  24. ↑ Hall IR. (2003). Edible and Poisonous Mushrooms of the World. Timber Press.
  25. ↑ Bresinsky A, Besl H (1990). A Colour Atlas of Poisonous Fungi. Wolfe Publishing. pp. 126–9. ISBN   0-7234-1576-5.
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