MSA - Ecology/Pathology
Frank, Jonathan , Coffan, Robert , Southworth, Darlene .
Aquatic gilled mushrooms in the Rogue River in Oregon: a new species of Psathyrella.
Mushrooms with true gills have been observed fruiting underwater in the clear, cold, flowing waters of the Rogue River in Oregon. Fruiting bodies develop and mature in the main channel, constantly submerged, near aquatic vegetation, fruiting over a period of 11 weeks. Morphological characters place these specimens in Psathyrella (Basidiomycota), a large genus of little brown mushrooms with 414 species in North America. DNA sequences of the ITS region and a portion of the 28S ribosomal DNA gene place this fungus in Psathyrella sensu stricto near P. fontinalis, P. atomata, P. ramicola, P. brooksii and P. gracilis. Morphological characters are consistent with DNA evidence. Psathyrella aquatica forms long stipes and small diameter caps. Immature stages have a thin veil that is soon lost; cystidia are ventricose with subacute apices; gills lack pink gill edges. Based on molecular and morphological evidence, we propose that the underwater mushrooms are a new species, P. aquatica. 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 the 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 observation adds to the biodiversity of stream fungi that degrade woody substrates. Flowing rivers represent a new habitat for gilled mushrooms.
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1 - Southern Oregon University, Department of Biology, 1250 Siskiyou Blvd, Ashland, Oregon, 97520-5010, USA
2 - Southern Oregon University, Environmental Studies, Ashland, OR, 97520, USA
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM