|Major Groups > Gilled Mushrooms > Pale-Spored > Lepiotoid Mushrooms > Macrolepiota procera|
by Michael Kuo
In North America we appear to have several "parasol mushrooms" going under the name of the Eurasian species Macrolepiota procera. Many, if not all, of these species are undescribed and unnamed. For this reason I probably shouldn't do what I usually do, which is to combine the data from all of my collections of a given species, and create a lengthy and fairly precise description of the mushroom's physical features. What if my collections don't all represent the same thing? So I will offer a brief description, and then try to talk you into helping mycologists figure out what our North American Macrolepiota species are.
Defining features for the group include the tall stature and fairly large size (caps are usually 5–20 cm across when mature); the little bump in the center of the mature cap; the brown scales; the long, slender stem (10–20 cm at maturity) that features small brownish scales or chevrons; and the distinctive, double-edged ring, which slides freely up and down the stem. The flesh is whitish and soft. The gills are crowded, and free from the stem. The spore print is white. Parasol mushrooms tend to grow alone or scattered in late summer, in woods or at their edges, or in pastures—often on trails and in other disturbed-ground areas. They are apparently widely distributed on our continent, but much more common east of the Rocky Mountains.
The name Macrolepiota prominens is popularly applied in Québec and in the northeastern United States to a procera-like species that is slightly smaller than the average North American parasol, and lacks the contrasting brown bands of fibrils and scales on the stem. However, Macrolepiota prominens is, like Macrolepiota procera, a European species (originally described from Italy)—one that is suspected to be synonymous with Macrolepiota mastoidea (Vellinga, 2001f), which has a granular cap surface and can feature contrasting or non-contrasting stem ornamentation. In short, the name prominens is probably misapplied in a North American context, and there's a fair chance it may not be properly applied anywhere.
You Can Help!
Mycology needs your help in the effort to document, describe, and name the procera-like species of Macrolepiota on our continent. Please see the pages on collecting mushrooms for study, making spore prints, and describing mushrooms, along with the page for preserving specimens. These pages provide the basics for documenting collections. Robust, well-documented, well-dried collections are essential to figuring out what our Macrolepiota species are. If you (or your mycological society) are interested in helping, I urge you to make such collections and donate them, along with supporting documentation and photographs, to a public herbarium. If you would like help figuring out the process, or selecting a herbarium, feel free to contact me!
Thanks to Jenny Bower, Roger Eberhardt, and Matthew Porraro for documenting, collecting, and preserving versions of Macrolepiota procera for study; their collections are deposited in The Herbarium of Michael Kuo.
REFERENCES: (Kauffman, 1918; Kauffman, 1924; Smith, 1949; H. V. Smith, 1954; Smith, Smith & Weber, 1979; Weber & Smith, 1985; Arora, 1986; Phillips, 1991/2005; Lincoff, 1992; Metzler & Metzler, 1992; Horn, Kay & Abel, 1993; Barron, 1999; Vellinga, 2001f; Roody, 2003; Vellinga, de Kok & Bruns, 2003; McNeil, 2006; Miller & Miller, 2006; Kuo, 2007; Ge, Vellinga & Yang, 2010; Vizzini et al., 2011; Kuo & Methven, 2014.) Herb. Kuo 08239701, 09030501, 10030502, 08141701, 09231801, 09072001, 07242107.
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Cite this page as:
Kuo, M. (2022, June). Macrolepiota procera. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/macrolepiota_procera.html