''Butyriboletus regius'' (formerly ''Boletus regius''), commonly known as the royal bolete or red-capped butter bolete, is a

basidiomycete Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basi ...

fungus A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...

of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

'' Boletus'' found in China and Europe. ''B. regius'' has a pink cap, yellow flesh, and a reticulate pattern on the

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

Harry D. Thiers Harry Delbert Thiers (January 22, 1919 in Fort McKavett, Texas – August 8, 2000 in Ohio) was an American mycologist who studied and named many fungi native to North America, particularly California. Thiers taught mycology at San Francisco St ...

described a similar mushroom from

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

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 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 mushro ...

Taxonomy

The species was first described and illustrated by Julius Vincenz von Krombholz in 1832.

Common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

s for the mushroom include the red-capped butter bolete and the royal bolete. ''Butyriboletus regius'' was formerly classified as a member of the section ''Appendiculati'' of the genus ''Boletus''.

Molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

analysis demonstrated that this and related "butter bolete" species, including '' Boletus appendiculatus'', are

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

ally distinct from ''Boletus'', and the new genus '' Butyriboletus'' was created to contain them.

Description

The

fruit bodies The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life cyc ...

of ''Butyriboletus regius'' have caps that are initially convex before flattening out in maturity, reaching a diameter of wide. The cap surface is pink to red, occasionally with hints of yellow or brown, more so around the margin. Initially velvety to slightly

tomentose Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plant ...

(hairy) when young, these minute hairs tend to slough off with age, and the cap develops wrinkles and pits. The cap flesh is yellow, and slowly and erratically bruises blue in North American specimens. The pores on the underside of the cap are angular, and measure about 1–2 per millimetre. The color of the pore surface is bright yellow to start, but eventually darkens somewhat, and will stain blue with damage. The depth of the tubes comprising the pores extends to . The

measures long by thick, and typically has a thick, bulbous base. It is solid (i.e., not hollow), and a bright yellow color, often with reddish tones, particularly near the base of the stem. The stem surface can be covered with fine yellow reticulations either throughout its length, or just on the upper portion. ''Butyriboletus regius'' produces an olive-brown spore print. Its smooth,

hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

(translucent)

spore In biology, a spore is a unit of sexual 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 plants, algae, f ...

s are roughly elliptical to somewhat

fusoid Fusiform means having a spindle-like shape that is wide in the middle and tapers at both ends. It is similar to the lemon-shape, but often implies a focal broadening of a structure that continues from one or both ends, such as an aneurysm on a b ...

(wider in the middle and tapering toward the ends) to more or less cylindrical, and have dimensions of 12–17 by 4–5

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

Chemical tests A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wit ...

can be used to help identify ''Butyriboletus regius'' in the field. 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 ...

will stain a pale purple color if FeSO₄ is applied; this same test will turn the flesh grayish.

Habitat and distribution

''Butyriboletus regius'' is an

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

l species with a broad

host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman * Michel Host ...

range, and associates with

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

and

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 single ...

s, particularly

fir Firs (''Abies'') are a genus of 48–56 species of evergreen coniferous trees in the family (biology), family Pinaceae. They are found on mountains throughout much of North America, North and Central America, Europe, Asia, and North Africa. The ...

. Fruit bodies grow singly, scattered about, or grouped together. In North America, they usually appear from August to November, although they also appear between May and June. The North American distribution includes the

Pacific Northwest The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...

states of

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

, and

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...

, where its frequency of occurrence ranges from "rare to locally abundant". It is rare in Europe, appearing on the

Regional Red List A Regional Red List is a report of the threatened status of species within a certain country or region. It is based on the IUCN Red List of Threatened Species, an inventory of the conservation status of species on a global scale. Regional Red ...

of several countries, and is considered

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...

in the Czech Republic. The species has also been recorded from China.

References

External links

* * {{Taxonbar, from1=Q96637355, from2=Q1062508 regius Edible fungi Fungi described in 1832 Fungi of China Fungi of Europe Fungi of North America

Taxonomy

Description

Habitat and distribution

See also

References

External links