Boletus regius Krombholz
Naturg. Abb. Schw. 2:3. 1832.

Common Name: Butter bolete

• Pileus

  Cap 8.0-15.0 (20) cm broad, strongly convex, expanding to plano-convex; margin incurved, becoming decurved to plane in age; surface subviscid when moist, otherwise dry, with irregular bumps, pits and depresssion, at first ornamented with patches of appressed fibrils, these often wearing away in age, then appearing glabrous; color rose-red to pale-pink, quickly fading with exposure to light to various combinations of buff, tan, or dull pale-yellow; context lemon-yellow, firm, up to 2.5 cm thick, slowly bluing when cut or injured, bluing reaction strongest just above the tube layer; odor mild; taste mild, pleasant.

• Hymenophore

  Pores lemon-yellow when young, 2-3 per mm, maturing to dingy-yellowish with a slight olivaceous tint, 1-2 per mm in age, bluing when bruised; tubes adnate in attachment, becoming depressed in age, up to 2.5 cm long, pale-yellow, bluing like the pores.

• Stipe

  Stipe 5.0-9.0 cm long, 3.0-4.0 cm thick at apex, clavate to sub-bulbous, solid, fleshy; surface of upper half conspicuously reticulate, the ornamentation and background color yellowish, sometimes becoming pallid, occasionally bluing when young; cortex yellowish, otherwise white, unchanging, often reddish at the base; partial veil absent.

• Spores

  Spores 13.0-15.5 x 4.0-5.0 µm, elliptical to slightly spindle-shaped in face-view, smooth, thin-walled; spore print olive-brown.

• Habitat

  Solitary, scattered to clustered, spring and fall under conifers in the Sierra, and in mixed confer-hardwood forests along the coast during the fall, possibly also in the spring.

• Edibility

  Edible and excellent.

• Comments

  Boletus regius is a beautiful, robust bolete with an aspect similar to Boletus edulis. A notable difference, however, is that Boletus regius has a rose-pink cap while Boletus edulis has a brownish cap. Additionally, the pore surface and stipe reticulation of Boletus regius are yellowish, compared to pallid in Boletus edulis. A final distinction is the tendency for the pores of Boletus regius to blue, a feature absent in Boletus edulis. Spring fruitings of Boletus regius in the Sierra should be compared with Boletus pinophilus, a close relative of Boletus edulis, and the occasional fruiting of Boletus rubripes. Boletus pinophilus has a somewhat similarly colored cap when young, pinkish-brown to dull rusty-brown, but the pore surface in youth is pallid not lemon-yellow and the stipe reticulation light-brown over a cream-colored background. Boletus rubripes is easily distinguished by the lack of a reticulated stipe and a bitter taste. In coastal forests Boletus regius is often confused with a close relative, Boletus appendiculatus. The latter, however, has a rusty-brown to yellowish-brown cap as opposed to rose-pink in Boletus regius.

• 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.
  Thiers, H.D. (1966). California boletes II. Mycologia 58(6): 815-826.
  Thiers, H.D. (1975). California Mushrooms—A Field Guide to the Boletes. Hafner Press: New York, NY. 261 p. (WWW)

• Other Descriptions and Photos
  • John Kirkpatrick: Boletus regius (CP)
  • Michael Wood: Boletus regius (CP)
  • Michael Wood: Boletus regius (CP)
  • Michael Wood: Boletus regius (CP)
  • Michael Wood: Boletus regius (CP)
  • Boletes of California: Boletus regius (D & CP)
  • Hugh Smith: Boletus regius (CP)
  • Beverly Hackett: Boletus regius (I)
  • Boleslaw Kuznik -- Hunting for Mushrooms: Boletus regius (CP)
  • Mushroom Observer: Boletus regius (CP)
  • Arora (1986): p. 526 (D), pl. 133 (CP)
  • Bessette et al. (2000): p. 147 (D), p. 307 (CP)
  • Orr & Orr: p. 105 (D), pl. 34 (CP)
  • Thiers (1975): p. 47 (D)
  • Tylutki (1987): p. 28 (D), p. 29 (CP)
  
  

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