Pluteus petasatus (Fries) Gillet
Hyménomycètes de France: 142. 1838.

Common Name: none

• Pileus

  Cap 5-13.5 cm broad, convex to convex-umbonate, expanding to nearly plane, at maturity the disc sometimes depressed or raised; margin in youth, incurved, then decurved, finally plane; surface sticky when moist, otherwise dry, glabrous when young, often shiny, cream-colored with pale innate, brown fibrils concentrated at the disc, the latter occasionally becoming fibrillose to squamulose; in dry weather the cap sometimes squamulose overall; context white, unchanging, soft, up 1.5 cm thick, thin near margin; odor and taste of radish.

• Lamellae

  Gills free, crowded, broad, pallid, becoming cream to pinkish, finally salmon pink; not marginate; lamellulae up to four-seried.

• Stipe

  Stipe 5-9 cm long, 1-1.5 cm thick, straight, the apex and base often enlarged, fleshy, solid at maturity; surface longitudinally striate at the apex, white, elsewhere smooth to slightly wrinkled, in age brownish fibrils sometimes developing at the base; partial veil absent.

• Spores

  Spores 5.5-7 x 4-5 µm, broadly ellipsoid to ovoid, smooth, with granular contents; spore print salmon-pink.

• Habitat

  Clustered, less commonly solitary, on rotting chips, woody debris or logs; fruiting in late summer in watered areas or after the fall rains.

• Edibility

  Edible.

• Comments

  This infrequent Pluteus is unusual in its clustered fruiting habit. Also characteristic is a relatively smooth, sometimes shiny cap that is pallid at the margin and brownish at the disc. A related, more common species is Pluteus cervinus. It is distinguished by an entirely brown cap. Volvariella speciosa is a distant cousin similar in stature, cap, and spore color, which may also fruit in wood chips. It is easily told from Pluteus petasatus by the presence of a volva. Another look-alike occasionally found in wood chips is Agaricus californicus. It has a similar colored, though not nearly as shiny cap, and can be differentiated by a partial veil and at maturity, free chocolate-colored gills.

• References

  Banerjee, P. & Sundberg, W.J. (1995). The Genus Pluteus Section Pluteus (Pluteaceae, Agaricales) in the Midwestern United States. Mycotaxon 53: 189-246.
  Bas, C., Kyper, T.W., Noordeloos, M.E. & Vellinga, E.C. (1990). Flora Agaricina Neerlandica -- Critical monographs on the families of agarics and boleti occuring in the Netherlands. Volume 2. Pluteaceae, Tricholomataceae. A. A. Balkema: Rotterdam, Netherlands. 137 p.
  Orton, P.D. (1986). British Fungus Flora: Agarics and Boleti. Vol 4. Pluteaceae: Pluteus & Volvariella. Royal Botanic Garden: Edinburgh, Scotland. 99 p.
  Singer, R. (1956). Contributions Towards a Monograph of the Genus Pluteus. Trans. Br. Mycol. Soc. 39(2): 145-232.

• Other Descriptions and Photos
  • Fred Stevens: Pluteus petasatus (CP)
  • Michael Wood: Pluteus petasatus (CP)
  • Mushroom Observer: Pluteus petasatus (CP)
  • Arora (1986): p. 255 (D & P)
  • Bas et al. (1990): P. 37 (D & I)
  • Bessette et al.: p. 62 (D & CP)
  • Breitenbach & Kränzlin (vol. 4): sp. 115 (D, I, & CP)
  • Orton: p. 24 (D), fig. 46 (I)
  • Phillips: p. 138 (CP), p. 139 (D)
  
  

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