''Austroboletus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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

in the family

Boletaceae The Boletaceae are a Family (biology), family of mushroom-forming fungi, primarily characterised by small pores on the spore-bearing hymenium, hymenial surface (at the underside of the mushroom), instead of Lamella (mycology), gills as are found ...

. The widely distributed genus contains species that form

mycorrhiza A mycorrhiza (; , mycorrhiza, or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the plant's rhizosphere, the plant root system and its surroundings. Mycorrhizae play ...

l relationships with plants.

Taxonomy

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

subgenus In biology, a subgenus ( 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 between the ge ...

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 gills. ...

'' 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 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 ...

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

Porphyrellus ''Porphyrellus'' is a genus of fungi of the family Boletaceae The Boletaceae are a Family (biology), family of mushroom-forming fungi, primarily characterised by small pores on the spore-bearing hymenium, hymenial surface (at the underside of ...

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

molecular genetics Molecular genetics is a branch 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 st ...

study, Wu and colleagues defined 22

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

s within the Boletaceae. They found the genus as understood to be

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

– 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'', '' Mucilopilus'' 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 (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 ...

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 Java ...

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 plant ...

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 basidiomycete 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 (: 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 are o ...

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 New Caledonia ( ; ) is a group of islands in the southwest Pacific Ocean, southwest of Vanuatu and east of Australia. Located from Metropolitan France, it forms a Overseas France#Sui generis collectivity, ''sui generis'' collectivity of t ...

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

l relationships with plant species.

Species

Index Fungorum ''Index Fungorum'' is an international project to index all formal names (scientific names) in the fungus kingdom. As of 2015, the project is based at the Royal Botanic Gardens, Kew, one of three partners along with Landcare Research and th ...

lists 38 valid species in the genus ''Austroboletus''.

References

External links

* {{Authority control Boletales genera Boletaceae