''Austroboletus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

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

in the family

Boletaceae The Boletaceae are a family of mushroom-forming fungi, primarily characterised by small pores on the spore-bearing hymenial surface (at the underside of the mushroom), instead of gills as are found in most agarics. Nearly as widely distributed ...

. The widely distributed genus contains 28 species that form mycorrhizal relationships with plants.

Taxonomy

E. J. H. Corner originally defined ''Austroboletus'' as a

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed betw ...

of ''

Boletus ''Boletus'' is a genus of mushroom-producing fungi, comprising over 100 species. The genus ''Boletus'' was originally broadly defined and described by Carl Linnaeus in 1753, essentially containing all fungi with hymenial pores instead of gil ...

'' in his 1972 work ''Boletus in Malaysia'', before it was raised to genus level in 1979 by mycologist Carl B. Wolfe. The

type species In 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 species that contains the biological type specimen( ...

is ''Austroboletus dictyotus'', a fungus originally described by Karel Bernard Boedijn in 1960 as a member of genus ''

Porphyrellus ''Porphyrellus'' is a genus of fungi 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 c ...

''. The generic name ''Austroboletus'' means "southern bolete". In a 2014

molecular genetics Molecular genetics is a sub-field of biology that addresses how differences in the structures or expression of DNA molecules manifests as variation among organisms. Molecular genetics often applies an "investigative approach" to determine the ...

study, Wu and colleagues defined 22 clades within the Boletaceae. They found the genus as understood to be

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

– composed of two distinct lineages. One with pitted stipes, which remained as ''Austroboletus'', while those with smoother stipes were moved to '' Veloporphyrellus''. They delineated a subfamily Austroboletoideae, which contained genera with pitted spores, including ''Austroboletus'', ''

Fistulinella ''Fistulinella'' is a genus of bolete fungi in the family Boletaceae. The genus has a pantropical distribution, and contains 15 species. ''Fistulinella'' was circumscribed by German mycologist Paul Christoph Hennings Paul Christoph Henning ...

'', ''

Mucilopilus ''Fistulinella'' is a genus of bolete fungi in the family Boletaceae. The genus has a pantropical distribution, and contains 15 species. ''Fistulinella'' was circumscribed by German mycologist Paul Christoph Hennings Paul Christoph Henning ...

'' and ''Veloporphyrellus''. These genera were notable in the family in that their fruit bodies generally do not change colour when bruised.

Description

Although they resemble other boletes macroscopically, ''Austroboletus'' is differentiated microscopically with

spores 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, ...

that are pitted, rather than smooth. The spore colour ranges from lilac- or pinkish-brown to wine-coloured. The pores and tubes are whitish. Members of the genus have a distinctive stipe marked by a coarse reticulate or lacunar (pitted) pattern—most prominent in species native to the western Pacific. The

caps Caps are flat headgear. Caps or CAPS may also refer to: Science and technology Computing * CESG Assisted Products Service, provided by the U.K. Government Communications Headquarters * Composite Application Platform Suite, by Java Caps, a Ja ...

are usually dry when young, and sometimes sticky in maturity, with a surface texture ranging from smooth to

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 plan ...

to scaly. Microscopically, ''Austroboletus'' lacks

clamp connection A clamp connection is a hook-like structure formed by growing hyphal cells of certain fungi. It is a characteristic feature of Basidiomycetes fungi. It is created to ensure that each cell, or segment of hypha separated by septa (cross walls), rece ...

s in the hyphae, and the presence of pleurocystidia and cheilocystidia (

cystidia A cystidium (plural cystidia) is a relatively large cell found on the sporocarp of a basidiomycete (for example, on the surface of a mushroom gill), often between clusters of basidia. Since cystidia have highly varied and distinct shapes that ar ...

on the pore face and edge, respectively) is variable.

Habitat, distribution, and ecology

Members of the genus are found mainly in the tropics, as well as Australia, New Zealand and New Caledonia in the southern hemisphere and Japan and North America in the Northern Hemisphere. Two species are found in North America: '' A. gracilis'' and '' A. subflavidus''. The majority of ''Austroboletus'' species form mycorrhizal relationships with plant species.

Species

Index Fungorum ''Index Fungorum'' is an international project to index all formal names (scientific names) in the fungus kingdom. the project is based at the Royal Botanic Gardens, Kew, one of three partners along with Landcare Research and the Institute of M ...

lists 27 valid species in ''Austroboletus''. *'' A. amazonicus'' A.M. Vasco-Pal. & C. López-Quint. (2014) *'' A. cornalinus'' (Perr.-Bertr. & R.Heim)

E.Horak Egon Horak (born Innsbruck in 1937) is an Austrian mycologist who has described more than 1000 species of fungi, including many from the Southern Hemisphere, particularly New Zealand and South America. He was an executive editor of the scientific ...

(1980) *'' A. dictyotus'' (Boedijn) Wolfe (1980) *'' A. eburneus'' Watling & N.M.Greg. (1986) *'' A. festivus'' (Singer) Wolfe (1980) *'' A. fusisporus'' (Kawam. ex Imazeki & Hongo) Wolfe (1980) *'' A. graciliaffinis'' Singer (1988) :Spores are elliptical (in face view) or

fusiform 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 ...

(in profile view), with average dimensions of 16.7 by 7.7

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 Uni ...

. *'' A. gracilis'' (Peck) Wolfe (1980) :The pore surface is initially whitish, then later matures to pinkish or flesh-colored. The stipe is typically slim. *'' A. heterospermus'' (R.Heim & Perr.-Bertr.) Singer (1983) *'' A. lacunosus'' (Kuntze) T.W.May & A.E.Wood (1995) *'' A. latitubulosus'' E.Horak (1980) *'' A. longipes'' (Massee) Wolfe (1980) *'' A. malaccensis'' (Pat. & C.F.Baker) Wolfe (1980) *'' A. mucosus'' (Corner) Wolfe (1980) *'' A. mutabilis'' Halling, Osmundson & M.A. Neves (2006) *'' A. neotropicalis'' Singer, J.García & L.D.Gómez (1991) *'' A. occidentalis'' Watling & N.M.Greg. (1986) *'' A. olivaceoglutinosus'' K.Das & Dentinger (2015) *'' A. olivaceus'' Singer (1983) :Spores are elliptical (in face view) or

(in profile view), with average dimensions of 12.9 by 5.9

. *'' A. purpurascens'' (Heinem.) E.Horak (1980) *'' A. rarus'' (Corner) E.Horak (1980) *'' A. rionegrensis'' (Singer & I.J.Araujo) Singer (1983) *'' A. rostrupii'' (Syd. & P.Syd.) E.Horak (1980) *'' A. rubiicolor'' (Corner) E.Horak (1980) *'' A. schichianus'' (Teng & L.Ling) E.Horak (1980) *'' A. subflavidus'' (Murrill) Wolfe (1980) :The cap color ranges from whitish to pale grayish yellow; the mushroom has a bitter taste. *'' A. subvirens'' (Hongo) Wolfe (1980) *'' A. trinitatensis'' Wolfe (1988) *'' A. tristis'' (Pat. & C.F.Baker) Wolfe (1980)

References

External links