Ascomycetes From North Temperate Lakes in Wisconsin
A comprehensive study of freshwater ascomycetes in seven lakes in northern Wisconsin was carried out. These lakes are part of the Long Term Ecological Research (LTER) project and have been the subject of limnological studies since the early 1900's. Our knowledge of freshwater ascomycetes is fairly recent and based on studies done in the past 50 years. Freshwater ascomycetes are defined as species that occur on submerged or partially submerged substrata in aquatic habitats. To date, no studies focusing on systematic collection of freshwater ascomycetes in lentic habitats throughout a year exist. Thus, little or no information is available regarding their frequencies and distributions from season to season. In this study, monthly samples of submerged substrata were collected and examined for freshwater ascomycetes from 1994 to 1997. Eighty-two ascomycetes on different substrata were reported from the lakes. Eleven species and 2 genera are described as new. Two discomycetes, Dasyscyphus controversa and Hymenoscyphus scutulus; two pyrenomycetes, Gnomonia petiolorum and Phomatospora berkeleyi; and six loculoascomycetes, Chaetomastia typhicola , Macrospora typhicola, Massarina eburnea , Melanomma pulvis-pyrius, Phaeosphaeria caricis, and Roussoella intermedia were new records for freshwater. One discomycete, Lambertella advenula, and a loculoascomycete, R. intermedia, were reported for the first time from North America. The ratio of species of Discomycetes: Pyrenomycetes: Loculoascomycetes was 19: 35: 28. Pyrenomycetes were mostly restricted to woody substrata and Loculoascomycetes to herbaceous substrata. Species occurrences were not well correlated with changes in temperature, but pH may be an important factor in fungal distribution patterns among the lakes. In many cases, the distribution of species depended on the distribution of their substrata.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign