A false truffle or a hymenogastrale is any

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

fungus 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 ...

that has underground fruiting bodies that produce

basidiocarps In fungi, a basidiocarp, basidiome, or basidioma () is the sporocarp of a basidiomycete, the multicellular structure on which the spore-producing hymenium is borne. Basidiocarps are characteristic of the hymenomycetes; rusts and smuts do no ...

resembling the true

truffle A truffle is the Sporocarp (fungi), fruiting body of a subterranean ascomycete fungus, one of the species of the genus ''Tuber (fungus), Tuber''. More than one hundred other genera of fungi are classified as truffles including ''Geopora'', ''P ...

s of genus ''

Tuber Tubers are a type of enlarged structure that plants use as storage organs for nutrients, derived from stems or roots. Tubers help plants perennate (survive winter or dry months), provide energy and nutrients, and are a means of asexual reproduc ...

''. While rodents such as squirrels eat a wide variety of false truffle species, many are considered toxic (''

Scleroderma Scleroderma is a group of autoimmune diseases that may result in changes to the skin, blood vessels, muscles, and internal organs. The disease can be either localized to the skin or involve other organs, as well. Symptoms may include areas ...

'' species) or otherwise unpalatable and only a few are sought after as food for humans. The rodents exist in an almost symbiotic relationship with the false truffle. The false truffle depends on the rodents to help spread its spores as it does not have the ability to eject the spores themselves. The rodents are attracted to a scent produced by the false truffle and ingest the spores. Spores survive the intestinal tract of the rodents and are excreted in the fecal matter ready to germinate. During the evolutionary period of the false truffle it lost its mushroom cap shape and closed up to protect the spores from dryer or harsher conditions. As a result it lost the ability to discharge its spores, hence the need for animal spore distribution. It is thought that false truffles and truffles evolved to grow beneath the surface because of changing conditions on the surface. Because fungus is sensitive to moisture and temperature, it makes sense that one strategy of survival would be to go underground where the moisture content is more stable. The stipe also dramatically shortened because it no longer needed the length to help with spore dispersal; as a result, some species either lost the stipe or is still found inside the false truffles. Similar in appearance to true truffles, which are ascomycetes, false truffles are basidiomycetes. Different false truffle lineage can be traced to agarics, russulas, boletes, and chanterelles. All false truffles have a symbiotic mycorrhizal relationship with the trees and shrubs they coexist with: the trees give them sugars and they provide the trees with more water and nutrients. Whereas the interior of the true truffle is marbled and solid, the interior of the false truffle is mostly not marbled like the true truffle, but instead most have a pulp-like interior. Some species have a black-and-white appearance or a brown color; other species have a white interior. The interior differs according to species. Although there are no known poisonous species of false truffle, many are unpalatable.

References

Basidiomycota Fungus common names {{Basidiomycota-stub