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Agaricus silvicola

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

by Michael Kuo

Defining features for this widely distributed Agaricus include:

  • Woodland habitat;
  • A fairly smooth, white cap;
  • Yellow staining (rub the edge of the cap repeatedly);
  • "Placomycetoid" (tall and slender) rather than "campestroid" (short and stocky) stature;
  • A sweet (faintly anise- or almond-like) odor;
  • A yellow reaction to KOH;
  • Fairly short (5-7.5 µ) spores.

I am treating Agaricus abruptibulbus as a synonym of Agaricus silvicola, but some authors separate it on the basis of its abruptly bulbous stem.


Ecology: Saprobic; growing alone, scattered, or gregariously in woods or at the edges of woods; summer and fall (also winter in California); widely distributed in North America.

Cap: 5-18 cm; convex at first, becoming broadly convex or flat; dry; whitish, sometimes developing yellowish stains; smooth or with innate, pressed-down fibers at maturity; bruising yellow, especially along the margin.

Gills: Free from the stem; close; whitish at first, becoming pinkish to pinkish gray and eventually brown; when young covered by a whitish or yellowish-stained partial veil that usually features patches or a "cogwheel" pattern.

Stem: 5-20 cm long; up to 2.5 cm thick; equal, or with a slightly to substantially and abruptly swollen base; smooth, or with fine fibers below the ring; white, often developing yellowish stains; usually bruising yellowish; with a persistent, large ring.

Flesh: Thick and white throughout; often yellowing slightly when sliced, but not turning dramatically and instantly yellow in the base of the stem.

Odor and Taste: Odor sweet (reminiscent of anise or almonds) when young and fresh, becoming less distinctive; taste pleasant.

Chemical Reactions: Cap yellow with KOH.

Spore Print: Dark brown.

Microscopic Features: Spores 5-7.5 x 3.5-4.5 µ; elliptical; smooth.

REFERENCES: (Vittadini, 1832) Peck, 1872. (Saccardo, 1887; Kauffman, 1918 [Psalliota]; Smith, 1975; Freeman, 1979; Smith, Smith & Weber, 1979; Arora, 1986; States, 1990; Phillips, 1991/2005; Lincoff, 1992; Horn, Kay & Abel, 1993; Evenson, 1997; Barron, 1999; Roody, 2003; McNeil, 2006.) Herb. Kuo 09030502, 09230606.

"Agaricus sylvicola" is an alternate spelling.

Further Online Information:

Agaricus silvicola at MykoWeb
Agaricus sylvicola at Roger's Mushrooms
Agaricus abruptibulbus at Roger's Mushrooms


Agaricus silvicola

Agaricus silvicola

Agaricus silvicola

Agaricus silvicola

Agaricus silvicola

Agaricus silvicola

Agaricus silvicola

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