Agaricus bitorquis (Qu閘et) Saccardo
Syll. Fung. 5:998. 1887.

Common Name: Torq

Synonym: Agaricus rodmani Peck

• Pileus

  Cap 5-15 cm broad, convex, becoming broadly so in age, sometimes expanding to plane with an upturned margin; surface smooth, whitish, often with adhering dirt; flesh white, thick, firm, unchanging; odor and taste mild.

• Lamellae

  Gills free, close, pallid, becoming pale brown, blackish-brown at maturity.

• Stipe

  Stipe 4-10 cm long, 2-4 cm thick, stout, equal to enlarged below, solid; surface whitish, more or less smooth, sometimes with fine, appressed scales at the apex; veil membranous, thick, white, sheathing from the base of the stipe.

• Spores

  Spores 5-6.5 x 4-5.5 µm, smooth, elliptical; spore print chocolate brown.

• Habitat

  Scattered to gregarious in disturbed habitats, e.g. roadsides, paths, vacant lots etc., preferring heavy soils like those surrounding San Francisco Bay; fruiting from mid to late winter.

• Edibility

  Excellent; substantial size, firm texture, and good flavor make this one of the best Agaricus species for the table.

• Comments

  Agaricus bitorquis is recognized by a usually short, compact, stature, smooth, white, but frequently dirty cap, and partially emergent fruitings, i.e. often just breaking through the soil surface. It is most likely to be confused with A. bernardii, which is also white and similar in stature, but the latter has a distinct briny odor and the flesh turns pink when cut.

• Other Descriptions and Photos
  • Tom Duffy: Agaricus bitorquis (CP)
  • Michael Wood: Agaricus bitorquis (CP)
  • Michael Wood: Agaricus bitorquis (CP) -- from a Don Simoni growing kit
  • Michael Wood: Agaricus bitorquis (CP) -- closeup of veil
  • Michael Wood: Agaricus bitorquis (CP) -- closeup of veil
  • A Few Good Mushrooms: Agaricus bitorquis (D & CP)
  • Pilze, Pilze, Pilze: Agaricus bitorquis (CP)
  • National Botanic Garden of Belgium: Agaricus bitorquis (CP)
  • Botanische Staatssammlung M黱chen: Agaricus bitorquis (I)
  • Arora (1985): p. 321 (D & P), plate 80 (CP)
  • Arora (1991): p. 121 (D & CP)
  • Jordan: p. 222 (D & CP)
  • Kerrigan: p. 23 (D & CP)
  • Lincoff: p. 503 (D), plate 157 (CP)
  • Miller: sp. 215 (D) [Agaricus rodmani]
  • Phillips: p. 190 (CP), p. 191 (D)
  • Smith & Weber: sp. 169 (D & CP)

  (D=Description; I=Illustration; P=Photo; CP=Color Photo)