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"Agaricus haemorrhoidarius"

[ Basidiomycota > Agaricales > Agaricaceae > Agaricus . . . ]

by Michael Kuo

This is more of a call for help than a species page. Are you east of the Rocky Mountains, and have you seen a woodland Agaricus with a scaly to fibrillose brown cap and flesh that stains red when bruised or sliced? Science needs your help! The eastern North American species in this group are poorly known and poorly documented, and contributing your collection (don't worry; it's pretty easy) can help mycologists figure out how many "eastern bleeders" we have and how to separate them—and, more importantly, how this group evolved on our continent. Please visit this page for information on how to contribute a collection.

Western North America's red-staining, brown-capped species are better known (see Agaricus brunneofibrillosus and Agaricus amicosus for two examples). But in eastern North America the picture is not as clear, and mycologists are in great part relying on crusty old collections made a century ago, trying to figure out what Peck (1901) and Murrill (1922) meant by "Agaricus haemorrhoidarius." Your eastern North American field guide may treat this species unquestioningly (e.g. Kauffman 1918, McKnight & McKnight 1987, Barron, 1999), but the epithet haemorrhoidarius actually belongs to a European species now split by mycologists into Agaricus langei and Agaricus sylvaticus, while our continent's masterwork on Agaricus, recently published (2016) by Richard Kerrigan, insists that "[m]ore work is needed to document Sanguinolenti material of eastern North America, and to reconcile the nomenclature as reported with the diverse species that exist there" (219).

Pictured to the right is contributor Richard Nadon's collection of a haemorroidarius-like species in Québec, unfortunately not vouchered and placed in a public herbarium. And before you think I'm taking a jab at Richard, let me confess that I have collected a similar mushroom several times in northern Michigan and, not only did I not preserve the specimens, I didn't even illustrate them. I will not make that mistake again!

Thanks to Michelle Lierl for documenting, collecting, and preserving "Agaricus haemorrhoidarius" for study; her collection is deposited in The Herbarium of Michael Kuo.

REFERENCES: Peck, 1901; Kauffman, 1918; Murrill, 1922; Smith, 1940; McKnight & McKnight, 1987; Barron, 1999; Kerrigan, 2016. Herb. Kuo 09272201.

This site contains no information about the edibility or toxicity of mushrooms.


Agaricus haemorrhoidarius

Agaricus haemorrhoidarius

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Cite this page as:

Kuo, M. (2017, December). "Agaricus haemorrhoidarius." Retrieved from the MushroomExpert.Com Web site: haemorrhoidarius.html