Oysters: Pleurotoid Mushrooms

[ Basidiomycetes . . . ]

by Michael Kuo

Mushrooms with a "pleurotoid" habit grow on wood, have gills, and typically form semicircular or kidney-shaped caps that are either directly attached to the wood or are attached by means of a rudimentary, lateral stem. They often grow in loose or dense clusters, forming shelf-like groups. However, many pleurotoid mushrooms can develop more or less central stems, especially when they grow on the upper surface of a log--when the stemless, sideways fruiting strategy would not allow the mushroom to hold its gills so that the spores will catch air currents and be distributed.

The Oyster Mushroom, Pleurotus ostreatus, is the best known mushroom in this group, and its genus name gives the pleurotoid mushrooms their label. To be less technical, I am calling these mushrooms "oysters," but it should be pointed out that neither term indicates a taxonomic group of naturally related mushrooms; it is simply convenient, when identifying mushrooms, to narrow down the possibilities by lumping the oysters together. Species of Crepidotus, for example, have brown spore prints and belong in the family Cortinariaceae--while Pleurotus ostreatus has a lilac spore print and belongs in an entirely different family, the Pleurotaceae.

Pleurotus ostreatus is a well known and popular edible, but edibility is not known for most of the other oysters; I do not recommend experimenting.

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Crepidotus alabamensis:  Spore print brown; southeastern; caps 1-4 cm across, whitish; stem absent; best identified with microscopic features.

Crepidotus applanatus:  Spore print brown; widely distributed; caps 1-4 cm across, white becoming pale cinnamon brown; stem absent.

Hohenbuehelia mastrucata:  Spore print white; eastern; rare; caps 2-7 cm across, rubbery, dark gray with thick gelatinous spines; stem absent.

Lentinellus:  [Genus; many species pleurotoid.] Spore print white; variously distributed; gills with jagged edges.

Lentinellus ursinus:  Cap brown to buff, up to 10 cm across, fuzzy to hairy on inner 1/3; taste acrid; stem absent; widely distributed.

Panellus stipticus:  Spore print white; widely distributed but more common in the east; caps 1-3 cm, woolly, tan to off-white; lateral stem present; taste usually bitter.

Panus conchatus:  Spore print white; widely distributed; caps 4-17 cm, not hairy, purple-brown becoming paler brownish; off-center stem usually present.

Panus rudis:  Spore print white; widely distributed; caps 2-10 cm, densely hairy, purplish, reddish brown, pinkish brown, or tan; off-center stem usually present.

Phyllotopsis nidulans:  Spore print pale pink; widely distributed; caps 2-8 cm across, densely hairy, orange; stem usually absent or very rudimentary.

Pleurotus ostreatus:  Spore print white to lilac; widely distributed; fruiting in fall and winter; caps 4-15 cm across, smooth, brownish; stem usually absent unless growing on top of the log.

Pleurotus populinus:  Spore print white; montane and northern (in the range of Quaking Aspen and closely related trees); caps 4-15 cm across, smooth, whitish; stem usually absent unless growing on top of the log.

Pleurotus pulmonarius:  Spore print white to lilac; widely distributed; fruiting in summer; caps 2-15 cm across, smooth, whitish; stem usually absent unless growing on top of the log.

Schizophyllum commune:  Spore print white; widely distributed; cap 1-4 cm across, somewhat hairy, whitish or pale brownish; stem absent; gills thick and split or grooved in appearance.

References

Aime, M. C. (2001). Biosystematic studies in Crepidotus and the Crepidotaceae. Doctoral dissertation, Virginia Polytechnic and State University. Available online:
http://scholar.lib.vt.edu/theses/available/etd-05052001-173519/unrestricted/final.pdf

Aime. M. C., R. Vilgalys & O. K. Miller (2005). The Crepidotaceae (Basidiomycota, Agaricales): Phylogeny and taxonomy of the genera and revision of the family based on molecular evidence. American Journal of Botany 92: 74-82. Available online here.

Alberto, E. et al. (1998). Reevaluation of Hohenbuehelia nigra and species with close affinities. Mycologia 90: 142-150.

Arora, D. (1986). Mushrooms demystified: A comprehensive guide to the fleshy fungi. Berkeley: Ten Speed Press. 959 pp.

Bandala, V. M. & Montova, L. (2000). A taxonomic revision of some American Crepidotus. Mycologia 92: 341-353.

Bunyard, B. A. et al. (1996). Ribosomal DNA analysis for resolution of genotypic classes of Pleurotus. Mycological Research 100: 143-150.

Buyck, B. & Horak, E. (1999). New taxa of pleurotoid Russulaceae. (1999). Mycologia 91: 532-537.

Guzman, G. et al. (1994). Studies in the genus Pleurotus, III. The varieties of P. ostreatus-complex based in interbreeding strains and in the study of basidiomata obtained in culture. Mycotaxon 50: 365-378.

Hesler, L. R. & Smith, A. H. (1965). North American species of Crepidotus. New York: Hafner. 187 pp. An online version of this book is available at the University of Michigan Herbarium Web site; click here to see it (URL too long for duplication)

Luther, B. S. & Redhead, S. A. (1981). Crepidotus cinnabarinus in North America. Mycotaxon 12: 417-430.

Mansur, M. et al. (2003). The white-rot fungus Pleurotus ostreatus secretes laccase isozymes with different substrate specificities. Mycologia 95: 1013-1020.

Miller, O. K. Jr. (1970). The genus Panellus in North America. The Michigan Botanist 9: 17-30.

Penas, M. M. et al. (2004). Structure of gene coding for the fruit body-specific hydrophobin Fbh1 of the edible basidiomycete Pleurotus ostreatus. Mycologia 96: 75-82.

Petersen, R. H. & Krisai-Greilhuber, I. (1996). An epitype specimen for Pleurotus ostreatus. Mycological Research 100: 229-235.

Petersen, R. H. et al. (no date). Biological species of Pleurotus. Retrieved from the University of Tennessee Web site: http://fp.bio.utk.edu/mycology/Pleurotus/pleurotusindex.htm

Redhead, S. A. (1986). Mycological observations 15-16: On Omphalia and Pleurotus. Mycologia 78: 522-528.

Smith, A. H., Smith, H. V. & Weber, N. S. (1979). How to know the gilled mushrooms. Dubuque, Iowa: Wm. C. Brown. 334 pp.

Thorn, R. G. & Barron, G. L. (1986). Nematoctonus and the tribe Resupinateae in Ontario, Canada. Mycotaxon 25: 321-453.

Vilgalys, R. & Sun, B. L. (1994). Ancient and recent patterns of geographic speciation in the oyster mushroom Pleurotus revealed by phylogenetic analysis of ribosomal DNA sequences. Proceedings of the National Academy of Sciences 91: 4599-4603.

Vilgalys, R. & Sun, B. L. (1994). Assessment of species distribution in Pleurotus based on trapping of airborne basidiospores. Mycologia 86: 270-274.

Zervakis, G. & Balis, C. (1996). A pluralistic approach in the study of Pleurotus species with emphasis on compatibility and physiology of the European morphotaxa. Mycological Research 100: 717-731.

Cite this page as:

Kuo, M. (2005, February). Oysters: Pleurotoid mushrooms. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/pleurotoid.html