Carol Shearer


Emeritus Professor of Plant Biology

655 Morrill MC-116
(217) 333-2796


Ph.D., 1971, University of Maryland


In freshwater habitats, leaves and branches of riparian vegetation are important as a food resource for stream heterotrophs. Fungi serve as intermediaries in making this resource more palatable and nutritious for aquatic invertebrates. We are interested in finding out why certain fungal species are more successful in colonizing resources initially, why other species are able to displace initial colonists over time, and how environmental factors influence colonization and decomposition processes. Field and laboratory studies are used to determine the relative importance of intrinsic characteristics of species that comprise their overall ability to colonize and decompose resources. These characteristics include: spore germination and germ tube elongation rates, growth rates, enzymatic capabilities, and ability to produce and resist antibiotics. Interspecific interactions among fungal species and between fungi and other organisms, such as grazing invertebrates, are also important determinants of species success in resource colonization. Field and laboratory experiments in which the interacting species are manipulated are used to determine the effects of species interactions on colonization processes.

Systematic studies in my laboratory deal with two general areas: fungal geography and biodiversity and phylogenetic relationships in Ascomycetes. The number of fungal species has been conservatively estimated at 1.5 million but only about 69,000 species actually have been collected and described. The freshwater ascomycetes, a group that has only recently been studied, are very poorly known. As part of the effort to determine fungal biodiversity as it relates to latitude, we are collecting fresh-water ascomycetes and their asexual states along latitudinal gradients through North America, which encompass arctic through tropical biomes. Species are collected, identified, described if new or rare, isolated in pure culture, and tested for the production of bioactive compounds.

Phylogenetic relationships among ascomycete taxa are poorly understood. This is especially true for aquatic and marine species which have undergone convergent evolution in response to habitat. We use cladistic analyses of morphological and molecular sequence data to resolve relationships among morphologically similar freshwater, marine and terrestrial species.


Oh, H., D.C. Swenson, J.B. Gloer and C.A. Shearer. 2003. New bioactive rosigenin analogues and aromatic polyketide metabolites from the freshwater aquatic fungus Massarina tunicata. J. Nat. Prod. 66: 73–79.


Campbell, J., C.A. Shearer, J.L. Crane, and P. Fallah. 2003. A reassessment of two freshwater ascomycetes, Ceriospora caudae-suis and Submersisphaeria aquatica.  Mycologia 95: 41–53.


Schmit, J.P. and C.A. Shearer. 2003. A checklist of mangrove-associated fungi, their geographical distribution and known host plants. Mycotaxon 85: 423–477.


Campbell, J., J. Anderson, and C.A. Shearer. 2003. Systematics of Halosarpheia based on morphological and molecular data. Mycologia: 95:532–553


Raja, H. A., J. Campbell, and C.A. Shearer. 2003. Freshwater ascomycetes:  Cyanoannulus petersenii, a new genus and species from submerged wood. Mycotaxon 78: 1–17.


Li C., Nitka M, Gloer J.B., Campbell J. and Shearer C.A. 2003. Annularins A-H: new polyketide metabolites from the freshwater fungus Annulatascus triseptatus. J. Nat. Prod. 66: 1302–1306.


Shearer, C.A., Deborah M. Langsam and Joyce E. Longcore. 2004. Fungi in Freshwater Habitats. Chapter 23 In: Measuring and Monitoring Biological Diversity: Standard Methods for Fungi. Mueller, G. M., G. F. Bills, and M. S. Foster, Eds. Smithsonian Institution Press, Washington, D.C. 777 pp.


Campbell, J. and C.A. Shearer. 2004. Annulusmagnus and Ascitendum, two new genera in the Annulatascaceae. Mycologia 96: 821-832. Mycologia 96: 821– 832.


Schmit, J.P., and C.A. Shearer. 2004. Geographic and host distribution of lignicolous mangrove microfungi. Botanica Marina 47: 496–500.


Reátegui R, Gloer JB, Campbell J and Shearer CA. 2005. Ophiocerins A-D: New Tetrahydropyran derivatives from the freshwater aquatic fungus Ophioceras venezuelense. J. Nat. Prod. 68: 701–705.


Sina M. Adl, Alastair G.B. Simpson, Mark A. farmer, Robert A.  Andersen, Roger A. Anderson, John Barta, Samuel Bowser, Guy Brugerolle, Robert Fensome, Suzanne Fredericq, Timothy Y. James, Sergei Karpov, Paul Kugrens, John Krug, Chris Lane, Louise A. Lewis, Jean Lodge, Denis H. Lynn, David Mann, Richard M. McCourt, Leonel Mendoza, Ojvind Moestrup, Sharon E. Mozeley-Standridge, Thomas A. Nerad, Carol Shearer, Frederick Spiegel, Max F.J.R. Taylor. 2005. The new higher level classification of eukaryotes with emphasis on the taxonomy of protists. Journal of Eukaryotic Microbiology 52(5): 399–451.


Raja, H., A. Ferrer, and C.A. Shearer. 2005. Aliquandostipite crystallinum, a new species from submerged wood in freshwater habitats. Mycotaxon: 207–215.


Ferrer, A. and C.A. Shearer. 2005. New records and a new species of Canalisporium from aquatic habitats in Panama. Mycotaxon 93: 179–188.


Campbell, J., C. A. Shearer and L. Marvanová. 2006. Evolutionary relationships among aquatic anamorphs and teleomorphs: Lemonniera, Margaritispora, Goniopila. Mycol. Res. 110(9):  1025–1033.


Anderson, J.L., J. Beever, and C.A. Shearer. 2006. Eight polymorphic microsatellite loci for the aquatic fungus Tetracladium marchalianum. Molecular Ecology Notes 6(3): 703–706.


Raja, H. A. and C. A. Shearer. 2006. Arnium gigantosporum, a new ascomycete species from fresh water in Florida. Fungal Diversity 22: 219–225.


Miller, A. N., C. A. Shearer, M. Bartolata and S. M. Huhndorf. 2006. Cuspidatispora xiphiago gen. et sp. nov. from an eastern North American creek. Mycoscience 47: 218–233.


Sanjay V. Mudur, Dale C. Swenson, James B. Gloer, Jinx Campbell, and Carol A. Shearer. 2006. Heliconols A-C:  Polyketide-derived Hemiketals from the Freshwater Aquatic Fungus Helicodendron giganteum Glen-Bott (Helotiaceae) Organic Letters 8 (15): 3191–3194.


Raja, H.A. and C.A. Shearer. 2006. Jahnula species from North and Central America, including three new species. Mycologia 98: 319–332.


Raja, H.A., A.M. Stchigel, A.N. Miller, J.L. Crane, C.A. Shearer, and J. Guarro. 2006. Mitosporic euascomycete fungi from the Great Smoky Mountains National Park, including three new species. Fungal Diversity: Accepted.


Jiao, Ping, Dale C. Swenson, James B. Gloer, Jinx Campbell, and Carol A. Shearer. 2006. Decaspirones A–E, bioactive spirodioxynaphthalenes from the Freshwater aquatic fungus Decaisnella thyridioides. Journal of Natural Products:


Shearer, C.A., E. Descals, B. Kohlmeyer, J. Kohlmeyer, L. Marvanová, D. Padgett, D. Porter, H. Raja, J.P. Schmit, H. Thornton, & H. Voglmayr. 2007. Fungal biodiversity in aquatic habitats. Biodiversity and Conservation 16: 49-67.


Campbell, J., A. Ferrer, H. A. Raja, S. Sivichai, C. A. Shearer. 2007. Evolutionary relationships among taxa in the Jahnulales inferred from nuclear ribosomal DNA sequences. Canadian Journal of Botany 85: 873–882.


Ferrer, A. and C.A. Shearer. 2007. Three new species of Luttrellia from temperate and tropical freshwater habitats. Mycologia 99: 144–151


Ferrer, A. and C.A. Shearer. 2007. Megalohypha, a new genus in the Jahnulales from aquatic habitats in the tropics. Mycologia 99: 456–460.


Raja, H.A and C.A. Shearer. 2007. Freshwater ascomycetes: Aliquandostipite minuta (Jahnulales, Dothideomycetes), a new species from Florida. Mycoscience 48: 395–398.


Ferrer, A. and C.A. Shearer. 2008. Lucidascocarpa pulchrum, a new ascomycete genus and species from freshwater habitats in the American tropics. Mycologia: Accepted.


Raja, H.A. and C.A. Shearer. 2008. Freshwater Ascomycetes: new species from aquatic habitats in Florida. Mycologia: Accepted.


Simonis, J.L., H. Raja & C.A. Shearer. 2008. Extracellular  enzymes and soft-rot decay: Are ascomycetes important degraders in freshwater? Fungal Diversity: Accepted.


Shearer, C.A., P. Fallah, A. Ferrer and H. Raja. 2008. Freshwater Ascomycete Database:  (Continuously updated).