The Genus Cortinarius

[ Basidiomycetes > Agaricales > Cortinariaceae . . . ]

by Michael Kuo

Cortinarius is the largest genus of mushrooms in the world, containing an astounding number of species (often estimated well over a thousand). Although the mushrooms in Cortinarius are very diverse, it is usually pretty easy to figure out when you are looking at one, once you get the hang of it. First, they have cortinas covering their gills when young (hence the name of the genus)--though the tiny fibers of the cortina are sometimes ephemeral and soon disappear, leaving no trace of themselves. Secondly, the spore print is rusty brown and, as a result of the rusty brown spores, the mature gills of Cortinarius mushrooms are usually also rusty brown. Finally, they are terrestrial and mycorrhizal.

But while the genus may be more or less easy to identify, figuring out what species of Cortinarius you have found may be one of the most difficult challenges in mushroom mycology, compounded by the fact that there are few (if any) comprehensive, current and reliable keys available to the public. In short, identifying a Cortinarius to species is often best described as a Quixotic endeavor--or maybe not; Don Quixote did manage to accomplish a thorough assault on a windmill, which is more "accomplishment" than one often achieves with Cortinarius identification.

Those things said, a few species are fairly distinctive, and these are often featured in field guides. In fact, there is emerging DNA evidence that amateur Cortinarius identifiers may have avoided a long and ultimately unnecessary nightmare by applying some of the broad labels represented by the "species clusters" in many field guides. The DNA studies of Cortinarii that I am aware of have suggested that much of the species "splitting" done by mycologists in the last century did not reflect meaningful genetic differences. However, as the authors of one study carefully point out, "[r]esearch on the molecular systematics of Cortinarius, a species-rich mushroom genus with nearly global distribution, is just beginning" (Peintner et al., 2004).

Many Cortinarius species are poisonous, and a few are even deadly. Obviously, given the problems associated with accurate identification, you should not eat any of them, even if you have used a field guide and feel pretty sure of your identification, because "pretty sure" is about as sure as you can be--not quite enough when your life hangs in the balance.

At MushroomExpert.Com

Cortinarius alboviolaceus:  Cap dry, pale silvery lilac or whitish; gills at first pale purple; stem dry, silvery lilac, sheathed with white; growing under hardwoods throughout North America.

Cortinarius armillatus:  Cap dry, yellowish brown to reddish brown; gills at first dull cinnamon; stem dry, encircled by 2-4 red "bracelets"; growing under birch in northern North America.

Cortinarius bolaris:  Cap dry, covered with red scales; gills at first yellowish to dull cinnamon; stem dry, also covered with red scales; growing under hardwoods in eastern North America.

Cortinarius caperatus (Rozites caperata):  Cap dry, wrinkled, yellowish brown with a Kleenex-like coating when young; gills at first pale; stem dry, whitish to pale brownish, with a white ring; growing under conifers or hardwoods in eastern and northern North America.

Cortinarius corrugatus:  Cap distinctively corrugated, orange-brown to reddish brown; gills at first pale; stem dry, whitish to yellowish, usually without veil remnants; growing under Beech and other hardwoods.

Cortinarius cotoneus:  Cap dry and finely hairy or scaly, yellowish brown to olive brown, with a blackish center; gills at first yellow; stem dry, yellowish to olive above, sheathed when young with yellow; growing under conifers throughout North America and under Tanoak in California.

Cortinarius croceus:  Cap dry and silky, yellowish brown to olive brown; gills at first yellow; stem dry, yellowish to brownish below; growing under conifers throughout North America.

Cortinarius distans:  Cap moist to dry, cinnamon brown to brownish, changing color as it dries out; gills at first yellowish tan; stem dry or moist, brownish, with a white ring zone; growing under hardwoods in eastern North America.

Cortinarius hesleri:  Cap dry, finely silky, bright orange; gills at first bright orange; stem dry, orange; growing under oaks in eastern North America.

Cortinarius iodes:  Cap slimy, mottled with purple, yellow, and white; gills at first purple; stem slimy, pale to purplish; growing under hardwoods in eastern North America.

Cortinarius malicorius:  Cap dry and finely hairy or scaly, orangish brown to cinnamon brown; gills at first orange; stem dry, yellowish; growing under conifers throughout North America, especially common in the Northeast.

Cortinarius phoeniceus var. occidentalis:  Cap dry and finely hairy, deep red; gills at first blood red; stem dry, yellowish; growing under conifers in the Pacific Northwest.

Cortinarius pingue (Thaxterogaster pingue):  A "gastroid" Cortinarius; cap pale olive brown, sticky, never expanding to expose gills; gills reddish brown, poorly formed; cortina white, often disappearing; stem present or nearly absent; growing above ground or submerged, under conifers at high elevation in the Rocky Mountains and on the West Coast.

Cortinarius rubripes:  Cap moist or dry, purplish to cinnamon brown, changing color markedly as it dries out; gills at first pale or pale purplish; stem dry to moist, swollen at the base, bright red to fiery orange below; growing under hardwoods, possibly widely distributed.

Cortinarius semisanguineus:  Cap dry, silky, yellowish brown to cinnamon brown; gills at first blood red; stem dry, yellowish; growing under conifers across North America.

Cortinarius subpulchrifolius:  Cap dry, grayish or silver, eventually stained rusty or brownish in places; gills at first purplish; stem dry, silvery to lilac, sheathed with white; growing under hardwoods in the Great Lakes region.

Cortinarius trivialis:  Cap slimy, orange-brown; gills at first clay colored or lilac; stem slimy, banded, scaly; under hardwoods in western North America.

Cortinarius vanduzerensis:  Cap slimy, dark brown; gills at first pale brownish; stem slimy, pale lilac above and dark lilac below; growing under conifers in the Pacific Northwest.

Other Sites

The Danish site The Phlegmacium Website is devoted to subgenus Phlegmacium of Cortinarius, and includes photos of over 100 species found in Denmark.

The Norwegian site Key to Cortinarius subgenus Dermocybe in the Nordic Countries provides, well, exactly what it purports to provide. The key relies primarily on macrocharacters.

References

Ammirati, J. F. & Smith, A. H. (1969). Studies in the genus Cortinarius, I: Section Dermocybe, Cortinarius aureifolius complex. The Michigan Botanist 8: 175-180.

Ammirati, J. F. (1972). The section Dermocybe of Cortinarius. Ph. D. thesis, University of Michigan. 282 pp.

Ammirati, J. F. & Smith, A. H. (1972). Studies in the genus Cortinarius, II: Section Dermocybe, new and interesting species from Michigan. The Michigan Botanist 11: 13-25.

Ammirati, J. F. (1975). Cortinarius, section Dermocybe-–Cortinarius clelandii. Mycotaxon 3: 95-101.

Ammirati, J. F. & Smith, A. H. (1977). Studies in the genus Cortinarius, III: Section Dermocybe, new North American species. Mycotaxon 5: 381-397.

Ammirati, J. F. & Smith, A. H. (1984). Cortinarius II: A preliminary treatment of species in the subgenus Dermocybe, section Sanguinei, in North America, north of Mexico. McIlvainea 6: 54-64.

Ammirati, J. F. (1988). Dermocybe (or Cortinarius, subgenus Dermocybe): Some species in the sections Dermocybe, Holoxanthae, and Malicoriae. McIlvainea 8: 48-59.

Ammirati, J. F. (1988). Dermocybe (Cortinariaceae, Agaricales): North American names - new combinations, synonyms, and notes. Mycotaxon 33: 437-446.

Ammirati, J. F. (1989). Dermocybe, subgenus Dermocybe, section Sanguineae in northern California. Mycotaxon 34: 21-36.

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

Cripps, C. L. & Miller, O. K. Jr. (1994). A new Cortinarius from a mature aspen stand in Montana. Mycotaxon 50: 315-321.

Garnica, S. et al. (2003). Phylogenetic relationships of European Phlegmacium species (Cortinarius, Agaricales). Mycologia 95: 1155-1170.

Hansen, L. & Knudsen, H., eds. (1992). Nordic macromycetes Vol. 2: Polyporales, Boletales, Agaricales, Russulales. Copenhagen: Nordsvamp. 474 pp.

Hoiland, K. & Holst-Jensen, A. (2000). Cortinarius phylogeny and possible taxonomic implications of ITS rDNA sequences. Mycologia 92: 694-710.

Kauffman, C. H. (1932). Cortinarius. North American Flora 10: 282-348.

Liu, Y. J. et al. (1997). Phylogenetic relationships in Dermocybe and related Cortinarius taxa based on nuclear ribosomal DNA internal transcribed spacers. Canadian Journal of Botany 75: 519-532.

Moser, M. (1993). Studies on North American Cortinarii. III. The Cortinarius flora of dwarf and shrubby Salix associations in the alpine zone of the Windriver Mountains, Wyoming, USA. Sydowia 45: 275-306.

Moser, M. M. et al. (1995). Studies on North American Cortinarii I. New and interesting taxa from the greater Yellowstone area. Mycotaxon 55: 301-346.

Moser, M. M. & Ammirati, J. F. (1996). Studies in North American Cortinarii II. Interesting and new species collected in the North Cascade Mountains, Washington. Mycotaxon 58: 387-412.

Peintner, U. et al. (2002). Phylogeny of Rozites, Cuphocybe and Rapacea inferred from ITS and LSU rDNA sequences. Mycologia 94: 620-629.

Peintner, U. et al. (2002). Thaxterogaster is a taxonomic synonym of Cortinarius: New names and new combinations. Mycotaxon 81: 177-184.

Peintner, U. et al. (2002). Rozites, Cuphocybe and Rapacea are taxonomic synonyms of Cortinarius: New combinations and new names. Mycotaxon 83: 447-451.

Peintner, U. et al. (2004). Toward a better understanding of the infrageneric relationships in Cortinarius (Agaricales, Basidiomycota). Mycologia 96: 1042-1058.

Phillips, R. (1986). A provisional multi-access key to American species of Cortinarius, Inoloma & Telemonia (including Leprocybe, Sericeocybe and Hydrocybe). Published by the author. 45 pp.

Phillips, R. (1991). Mushrooms of North America. Boston: Little, Brown and Company. 319 pp.

Smith, A. H. (1939). Studies in the genus Cortinarius I. Contributions from the University of Michigan Herbarium 2. 43 pp.

Smith, A. H. (1942). New and unusual Cortinarii from Michigan, with a key to the North American species of subgenus Bulbopodium. Bulletin of the Torrey Botanical Club 69: 44-64.

Smith, A. H. (1944). New and interesting Cortinarii from North America. Lloydia 7: 163-235.

Smith, A. H. & Trappe, J. M. (1972). The higher fungi of Oregon’s Cascade Head Experimental Forest and vicinity - I. The genus Phaeocollybia (Agaricales) and notes and descriptions of other species in the Agaricales. Mycologia 64: 1138-1153.

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

Cite this page as:

Kuo, M. (2005, January). The genus Cortinarius. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/cortinarius.html