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Agaricus bernardii

[ Basidiomycetes > Agaricales > Agaricaceae > Agaricus . . . ]

Taxonomy in Transition: ...  > Agaricales > Lepiotoid Clade (J&V, 1998)

by Michael Kuo

Originally described from seaside dunes in France, Agaricus bernardii has since been found in other maritime ecosystems in Europe, on the Pacific and Atlantic coasts of our continent . . . and in Denver. Perhaps an enterprising Denver lawn care business imported sod or sand from a coastal area, or perhaps Agaricus bernardii is capable of adapting to diverse ecosystems.

The salient features of Agaricus bernardii--taught to me by Ellen Jacobson of the Colorado Mycological Society--include the sheathlike (rather than skirtlike) ring; the tough, red-staining flesh; the subscaly mature cap surface; and the inrolled cap margin. Microscopic features (see below) will confirm identification.


Ecology: Saprobic; growing alone, scattered, or gregariously in sand dunes, drainage areas near coastal and brackish waters, and under Monterey Cypress; also in lawns and grassy areas (and then sometimes forming fairy rings); summer and fall (or over winter in California); recorded along the Pacific and Atlantic coasts, and in Denver.

Cap: 5-21 cm; convex to broadly convex; whitish and fairly smooth when young, becoming cracked or subscaly and often developing brownish colors; dry; the margin strongly inrolled.

Gills: Free from the stem; close; pink becoming brown and then dark chocolate brown in maturity; covered with a white partial veil when in the button stage.

Stem: 4-13 cm long; up to 4 cm (or more) thick; more or less equal, or tapering to base when mature; with a sheathing white ring; solid; whitish to brownish, bruising reddish; smooth or finely hairy.

Flesh: Whitish; usually changing to pinkish or reddish when sliced; not yellowing, even in the base of the stem.

Odor and Taste: Mild (inland collections) or pungent and briny.

Chemical Reactions: Cap surface negative with KOH.

Spore Print: Dark chocolate brown.

Microscopic Features: Spores: 5-8 x 5-6.5 µ; elliptical. Cheilocystidia up to 60 x 17 µ; cylindrical; flexuous.

Agaricus halophilus Peck may be a synonym.

REFERENCES: Quélet, 1887. (Saccardo, 1887; Phillips, 1981; Arora, 1986; Kerrigan, 1986; Hansen & Knudsen, 1992; Challen, Kerrigan & Callac, 2003; Didukh et al., 2005.)

Agaricus bitorquis is quite similar, but does not stain red.

Further Online Information:

Agaricus bernardii at MykoWeb
Agaricus bernardii at Roger's Mushrooms


Agaricus bernardii

Agaricus bernardii

Agaricus bernardii

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Kuo, M. (2007, October). Agaricus bernardii. Retrieved from the MushroomExpert.Com Web site: