What Lies Beneath: A New Mushroom

January 01, 2008

SOU faculty and staff have discovered gilled mushrooms (as in mushroom gills, not fish gills!) growing underwater in the clear, cold, flowing waters of the Rogue River. This has never before been documented. Anywhere! The initial discovery was made by Robert Coffan, Adjunct Professor of Hydrology in the Environmental Studies Department. However, it was the collaborative efforts of his colleagues in the Biology Department, Darlene Southworth and Jonathan Frank, that verified its uniqueness. The research team has submitted a manuscript, which is currently under editorial review, to a scientific journal called Mycologia. Here is the manuscript abstract...

Abstract: Psathyrella aquatica is a new species of Basidiomycota with true gills that has been observed fruiting underwater in the clear, cold, flowing waters of the upper Rogue River in Oregon. Fruiting bodies develop and mature in the main channel, constantly submerged, near aquatic vegetation, and where observed fruiting over 11 weeks. ITS sequence data place this fungus in the genus Psathyrella. These appear to be truly underwater mushrooms and not mushrooms fruiting on wood recently washed into the river. Substrates include water-logged wood, gravel, and silty river bed. Water constrains spore dispersal. Spores were observed as wedge-shaped rafts released into a gas pocket under the cap. Underwater gills and ballistospores indicate a recent adaptation to the stream environment. This particular river habitat combines the characteristics of spring-fed flows, clear, cold, aerated water with woody debris in shallow depths on a fine volcanic substrate. The presence of nitrogen-fixing cyanobacteria near fruiting body attachment sites suggests a source of nitrogen in an otherwise clear stream. This observations adds to the biodiversity of stream fungi that degrade woody substrates. This is a new habitat for gilled mushrooms.