''Psathyrella aquatica'' is a species of

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 ...

from

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

, first described in the journal ''

Mycologia ''Mycologia'' is a peer-reviewed scientific journal that publishes papers on all aspects of the fungi, including lichens. It first appeared as a bimonthly journal in January 1909, published by the New York Botanical Garden under the editorship of W ...

'' in 2010. It represents the first ever report of a gilled

basidiomycete Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basid ...

fruiting underwater.

Taxonomy

Discovery

It was found by

Southern Oregon University Southern Oregon University (SOU) is a public university in Ashland, Oregon. It was founded in 1872 as the Ashland Academy, has been in its current location since 1926, and was known by nine other names before assuming its current name in 1997.Kre ...

professor Robert Coffan in the Rogue River in the U.S. state of

. Coffan and his colleagues, Darlene Southworth and Jonathan Frank, found the mushroom in 2005. The

biology Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and ...

department at Southern Oregon University confirmed that the mushroom was a unique discovery. Once their research was published, it was named one of the most significant species discovered in 2010. The

species epithet Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In Taxonomy (biology), taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany) ...

, ''aquatica'', is a

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

word meaning water or watery (relating to water, aquatic), in reference to the mushroom's habitat. They have so far been discovered in a 1 kilometer stretch of the river, and have an observed fruiting season of mid-June to late September''Underwater_Mushroom – Mycological Society of America''. (n.d.). Retrieved February 25, 2022, from https://msafungi.org/underwater_mushroom/ Many scientists were skeptical about describing this mushroom as a new species because of the hundreds of similar looking species in the

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 ...

Psathyrellaceae The Psathyrellaceae are a family of dark-spored agarics that generally have rather soft, fragile fruiting bodies, and are characterized by black, dark brown, rarely reddish, or even pastel-colored spore prints. About 50% of species produce frui ...

. Less than 1% of aquatic fungi are assumed to be discovered yet, and many are assumed to be microscopic, with only a small fraction thought to produce fruiting bodies.

Description

The

fruiting body 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 cyc ...

consists of a small convex cap and a long stipe. Its cap is brown, convex, and has gills underneath. The young mushroom develops a veil, which is lost as the mushroom grows to maturity. The mushroom's stipe appears to be quite strong, and is anchored up to 1.6 feet (0.5 m) deep in sediment, in order to stand up to the fast-moving river currents where it is primarily found. The stipe is covered in thin hair like structures.

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 ...

released by the gills stay in gas bubbles underneath the gills before floating to the top of the water to spread. Underwater gills and ballistospores suggest that its underwater adaption is a relatively recent one. When synthetically grown, ''P. aquatica'' are known to only fruit (produce stipe and cap) underwater. A study done in 2014 by one of the original authors of the discovery paper showed that this species only produces sporocarps when completely submerged under cold water.

Habitat

The mushrooms are found growing out of water-logged wood, silt, and gravel, a fine volcanic substrate, and were observed growing from youth to maturity completely underwater over 11 weeks. The mushroom grows submerged under the fast, cold, running water of the river. The water is spring-fed, aerated, and contains lots of woody debris and is shallow in depth. They are found growing about half a meter underneath the water. The mushroom is also found growing on land on either grassy banks or on gravel or water-logged wood next to the river.

Ecology

Though not enough is known about the species to consider it edible, scientist assume that it is a food source for small insects in the river. Though the river has low levels of

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

, nitrogen-fixing

cyanobacteria Cyanobacteria ( ) are a group of autotrophic gram-negative bacteria that can obtain biological energy via oxygenic photosynthesis. The name "cyanobacteria" () refers to their bluish green (cyan) color, which forms the basis of cyanobacteri ...

near mushroom discovery sites suggests they might provide a source of nitrogen.''Southern Oregon University: College of Arts and Sciences''. (2008, August 19). https://web.archive.org/web/20080819151450/http://www.sou.edu/cas/connections/connections0006.html

References

Aquatic fungi Psathyrellaceae Fungi of North America Fungi described in 2010 Fungus species {{Psathyrellaceae-stub