Hypogeous Fungi

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 cycle, while the rest of the life cycle is characterized by vegetative mycelial growth and asexual spore production.

The sporocarp of a basidiomycete is known as a '' basidiocarp'' or ''basidiome'', while the fruitbody of an ascomycete is known as an ''ascocarp''. Many shapes and morphologies are found in both basidiocarps and ascocarps; these features play an important role in the identification and taxonomy of fungi.

Fruitbodies are termed ''epigeous'' if they grow on the ground, while those that grow underground are '' hypogeous''. Epigeous sporocarps that are visible to the naked eye, especially fruitbodies of a more or less agaricoid morphology, are often called mushrooms. Epigeous sporocarps have mycelia that extend underground far beyond the mother sporocarp. There is a wider distribution of mycelia underground than sporocarps above ground. Hypogeous fungi are usually called truffles or false truffles. There is evidence that hypogeous fungi evolved from epigeous fungi. During their evolution, truffles lost the ability to disperse their spores by air currents, and propagate instead by animal consumption and subsequent defecation.

In amateur mushroom hunting, and to a large degree in academic mycology as well, identification of higher fungi is based on the features of the sporocarp.

The largest known fruitbody is a specimen of '' Phellinus ellipsoideus'' (formerly ''Fomitiporia ellipsoidea'') found on Hainan Island, part of China. It measures up to in length and is estimated to weigh between .

Ecology

A wide variety of animals feed on epigeous and hypogeous fungi. The mammals that feed on fungi are as diverse as fungi themselves and are called mycophages. Squirrels and chipmunks eat the greatest variety of fungi, but there are many other mammals that also forage on fungi, such as marsupials, mice, rates, voles, lemmings, deer, shrews, rabbits, weasels, and more. Some animals feed on fungi opportunisticaly, while others rely on them as a primary source of food. Hypogeous sporocarps are a highly nutritious primary food source for some small mammals like the Tasmanian Bettong. Evidence of this is that the composition of fungi in the diet of Tasmanian Bettong was positively correlated with body condition and growth rates of pouch young. Ectomycorrhizal or hypogeous fungi form a symbiotic relationship with small mycophagous mammals. Hypogeous sporocarps depend on small fungivorous mammals to disperse their spores since they are underground and cannot utilize wind dispersal like epigeous sporocarps.

Underground fungi also play a role is a three-way symbiotic relationship with small marsupials and Australian Eucalyptus forests. In Australian Eucalyptus forests, hypogeous sporocarp dispersal is positively affected by fires. After a fire, most if not all epigeous sporocarps are wiped out, leaving hypogeous sporocarps to be the primary source of fungi for small marsupials. The ability of hypogeous fungi to resist disasters, such as fire, could be due to their evolved ability to survive the digestive systems of animals in order to distribute. Sporocarps can also serve as a food source for other fungi. Sporocarps can be hosts to diverse communities of fungicolous fungi. Short-lived sporocarps that evolved little investment in defense mechanisms are more often victim to fungicolous fungi than long-lived sporocarps. Resupinate sporocarps, sporocarps that have a higher surface area to volume ratio, are hosts to a higher diversity of fungicolous fungi than pileate sporocarps.

See also

* Lamella – the gills
* Sporangium
* Stipe – the stalk

References

Further reading

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{{DEFAULTSORT:Sporocarp (Fungi)
Mycology
Fungal morphology and anatomy