''Cyanoboletus pulverulentus'', commonly known as the ink stain bolete, is a species of

bolete A bolete is a type of mushroom, or fungal fruiting body. It can be identified thanks to a unique cap. On the underside of the cap there is usually a spongy surface with pores, instead of the gills typical of mushrooms. A similar pore surface i ...

mushroom. All parts of the mushroom will stain dark bluish-black after handling. It is found in

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

and

mixed forest Temperate broadleaf and mixed forest is a temperate climate terrestrial habitat type defined by the World Wide Fund for Nature, with broadleaf tree ecoregions, and with conifer and broadleaf tree mixed coniferous forest ecoregions. These ...

s, particularly on moist soil on slopes and under

beech Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...

and

oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

trees. A common species, it is found in northern Asia, Europe, North Africa, Central and northern South America, and eastern North America. The mushroom hyperaccumulates

arsenic Arsenic is a chemical element; it has Symbol (chemistry), symbol As and atomic number 33. It is a metalloid and one of the pnictogens, and therefore shares many properties with its group 15 neighbors phosphorus and antimony. Arsenic is not ...

and therefore its

consumption Consumption may refer to: * Eating *Resource consumption *Tuberculosis, an infectious disease, historically known as consumption * Consumer (food chain), receipt of energy by consuming other organisms * Consumption (economics), the purchasing of n ...

should be limited.

Taxonomy

''Boletus pulverulentus'' was first described by German mycologist Wilhelm Opatowski in 1836. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''pulverulentus'' means "covered with powder" and refers to the somewhat dry powdery surface of the young

cap A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. The origin of the word "cap" comes from the Old French word "chapeau" which means "head co ...

and stalk. The fungus was transferred to the newly created genus ''

Cyanoboletus ''Cyanoboletus'' is a fungal genus in the family Boletaceae. Circumscribed in 2014, it contains four species: '' C. flavosanguineus'', '' C. rainisii'', '' C. sinopulverulentus'', and the type, '' C. pulverulentus''. The gener ...

'' in 2014, where it is the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

. Based on the 28S rDNA, North American collection of this fungus reported in the Genbank database (accession numbe
KF030313
does not match that from Europe.

Description

The cap is convex, flat when old, dark reddish-brown becoming lighter with age, and grows up to in diameter. The

cap cuticle The pileipellis is the uppermost layer of hyphae in the pileus of a fungal fruit body. It covers the trama, the fleshy tissue of the fruit body. The pileipellis is more or less synonymous with the cuticle, but the cuticle generally describes th ...

comprises a tissue layer of undifferentiated

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

e measuring 3–7

μm The micrometre (Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a unit of length in the International System ...

wide. The stalk is long and slender, bright yellow to orange yellow at the top, and reddish-brown at the base. The flesh is yellow, with a mild taste and immediately turns blackish-blue when handled. The

basidia A basidium (: basidia) is a microscopic spore-producing structure found on the hymenophore of reproductive bodies of basidiomycete fungi. The presence of basidia is one of the main characteristic features of the group. These bodies are also ...

(spore-bearing cells) measure 22–35 by 6–9

Spores In biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plant ...

are smooth, fusoid (fuse shaped) to elliptical, and measure 11–15 by 4–6 μm. The

spore print 300px, Making a spore print of the mushroom ''Volvariella volvacea'' shown in composite: (photo lower half) mushroom cap laid on white and dark paper; (photo upper half) cap removed after 24 hours showing warm orange ("tussock") color spore print. ...

colour is olive brown.

Similar species

The eastern North American lookalike '' Boletus oliveisporus'' can be distinguished from ''C. pulverulentus'' by the pink to reddish colour in the center section of its stipe. ''

Caloboletus ''Caloboletus'' is a fungal genus in the family Boletaceae. It was circumscription (taxonomy), circumscribed by Italian mycologist Alfredo Vizzini with ''Boletus calopus, Caloboletus calopus'' as the type species. The erection of ''Caloboletus'' ...

'', '' Lanmaoa'', and ''

Xerocomellus ''Xerocomellus'' is a genus of fungi in the family Boletaceae. The genus, as it was described in 2008, contained 12 species. However ''Hortiboletus rubellus, X. rubellus'' and ''Hortiboletus engelii, X. engelii'' were transferred to the new gen ...

'' species may be similar.

Habitat and distribution

ectomycorrhiza An ectomycorrhiza (from Greek ἐκτός ', "outside", μύκης ', "fungus", and ῥίζα ', "root"; ectomycorrhizas or ectomycorrhizae, abbreviated EcM) is a form of symbiotic relationship that occurs between a fungal symbiont, or mycobio ...

l species, ''C. pulverulentus'' forms associations with

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

ous and

trees, particularly

. Fruit bodies appear on the ground, usually singly, in woodland. The bolete is widely distributed, having been reported from northern Asia, Europe, North Africa, Central and northern South America, and eastern North America (from July to September). Reports of appearances in western North American could refer to the similar '' Cyanoboletus rainsii'', which stains greenish-black instead of bluish-black.

Toxicity

A recent study has revealed this mushroom hyperaccumulates

and therefore its consumption should be limited.

Uses

The mushrooms are

edible An edible item is any item that is safe for humans to eat. "Edible" is differentiated from " eatable" because it does not indicate how an item tastes, only whether it is fit to be eaten. Nonpoisonous items found in nature – such as some mushroo ...

, but not particularly desirable.

References

External links

{{Taxonbar, from=Q41596453 Boletaceae Edible fungi Fungi described in 1836 Fungi of Africa Fungi of Asia Fungi of Central America Fungi of Europe Fungi of South America Fungus species