Boletus truncatus (Singer, Snell, & Dick) Pouzar
Ceská Mycol. 20: 2. 1966.

Common Name: none

Synonym: Xerocomus truncatus Singer, Snell, & Dick

• Pileus

  Cap 5-10 cm broad, convex, broadly convex to nearly plane in age; surface dry, tomentose, brown to olive-brown, usually cracking early in development revealing underlying yellowish to pinkish tissue, the latter more prevalent toward the margin; flesh thick, light yellow, blueing irregularly when injured; odor mild, taste acidic.

• Hymenophore

  Pores +/- 1 per mm, dull yellow to yellowish-green, bruising rapidly blue; tubes up to 1.5 cm long, narrowly depressed near stipe, yellowish-green, quickly and strongly bruising blue.

• Stipe

  Stipe 5-10 cm long, 1.5-2.5 cm thick, solid, equal, or the base slightly narrowed; surface dry, smooth to slightly striate, yellowish at the apex, otherwise reddish; yellowish-green mycelium at base.

• Spores

  Spores 12-15 x 4.5-6 µm, smooth, elliptical to fusiform, truncate at one end; spore print olive-brown.

• Habitat

  Solitary to in small groups in hardwood/conifer woods from fall to mid-winter.

• Edibility

  Edible and good.

• Comments

  This nondescript bolete is closely related to and often confused with Boletus chrysenteron. Both have an olive-brown to brown tomentose cap typically areolate at maturity, similarly colored stipe, and yellowish mycelium at the base. Boletus truncatus, however, is less likely than B. chrysenteron to develop pinkish tones in cracks near the cap margin, and in our experience the pores bruise blue almost instantly, while in B. chrysenteron, this reaction takes several seconds with the blueing never as intense. Nonetheless, a microscope is required to make a positive identification. Boletus truncatus spores are, as the species name suggests, blunt or clipped at one end, those of B. chrysenteron, rounded.

• References

  Bessette, A.E., Roody, W.C. & Bessette, A.R. (2000). North American Boletes: A Color Guide to the Fleshy Pored Mushrooms. Syracuse University Press: Syracuse, NY. 400 p.
  Ladurner, H. & Simonini, G. (2003). Xerocomus s.l. Edizioni Candusso: Alassio. 527 p.
  Smith, A.H. & Thiers, H.D. (1971). The Boletes of Michigan. University of Michigan Press: Ann Arbor, MI. 426 p.
  Snell, W.H., Singer, R. & Dick, E.A. (1959). Notes on Boletes. XI. Mycologia 51(4): 564-577.
  Thiers, H.D. (1975). California Mushrooms—A Field Guide to the Boletes. Hafner Press: New York, NY. 261 p. (WWW)

• Other Descriptions and Photos
  • Darvin DeShazer: Boletus truncatus (CP) -- the bluing reaction on the pores is very strong and quick
  • Boleslaw Kuznik: Boletus truncatus (CP)
  • Boletes of California: Boletus truncatus (D & CP)
  • Boleslaw Kuznik -- Hunting for Mushrooms: Boletus truncatus (CP)
  • Bessette et al. (2000): p. 168 (D), p. 316 (CP)
  • Thiers (1975): p. 108 (D)
  • Tylutki (1987): p. 32 (D & P)
  
  

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