The Gomphidiaceae are a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

mushroom A mushroom or toadstool is the fleshy, spore-bearing Sporocarp (fungi), fruiting body of a fungus, typically produced above ground on soil or another food source. ''Toadstool'' generally refers to a poisonous mushroom. The standard for the n ...

-forming

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 order

Boletales The Boletales are an order of Agaricomycetes containing over 1300 species with a diverse array of fruiting body types. The boletes are the best known members of this group, and until recently, the Boletales were thought to only contain boletes. ...

. Unlike other boletes, all members of Gomphidiaceae (except for ''Gomphogaster'') are

agaric An agaric () is a type of fungal fruiting body characterized by the presence of a pileus (cap) that is clearly differentiated from the stipe (stalk), with lamellae (gills) on the underside of the pileus. It is a type of mushroom (or toadstool) ...

s, having

gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

instead of pores. Member genera include '' Chroogomphus'', '' Cystogomphus'', ''

Gomphidius ''Gomphidius'' is a genus of mushrooms, commonly known as spike-caps, that are members of the Boletales (suborder (biology), suborder Suillineae), or pored fungi. They appear to have gill-like structures which resemble those of Agaricales, agaric ...

'' and '' Gomphogaster'', the last being a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus (i.e. with a single species) that may be incorporated into Gomphidius in the future after molecular assessment. The similarly named genus '' Gomphus'' is unrelated to this family. Another genus ''Brauniellula'' has since been sunk into ''Chroogomphus''. Like all agarics, this group was formerly classified in

Agaricales The Agaricales are an order (biology), order of fungi in the division (mycology), division Basidiomycota. As originally conceived, the order contained all the agarics (gilled mushrooms), but subsequent research has shown that not all agarics are ...

. Nonetheless, many of the microscopic features of these fungi, such as

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

shape, strongly suggested an affinity with

. This was later confirmed through

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

investigation, which demonstrated that Gomphidiaceae are more closely related to boletes than the "true" agarics of the Agaricales and that the development of

in this group was an independent evolutionary event from the development of gills in the Agaricales. Molecular phylogenetic investigations have also demonstrated Gomphidiaceae are nested well within Boletales, being more closely related to Suillaceae than to

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 ...

, a finding that is supported by chemotaxonomic investigation of these groups. This family of fungi has been thought to be ectomycorrhizal, forming symbiotic relationship with their host trees, however, there is now evidence that many (and perhaps all) species in this group are

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

upon ectomycorrhizal boletes, in relationships that are often highly species-specific.

References

Further reading