Boletus regineus

Description

Boletus regineus is an edible and highly regarded mushroom of the genus Boletus that inhabits southwestern North America. The cap is wide, convex then flat, brown with a whitish dusting when young. The stalk is 5–17 cm long, 3–6 cm wide, clavate then equal, and whitish tan.

This mushroom is a close relative of Boletus edulis (King Bolete, Porcini). Although usually smaller and less common than its better-known cousin, Boletus regineus is considered by many mycologists to be equal in quality as table-fare. It is distinguished from the King Bolete by habitat preferencemixed hardwood/conifer woods in contrast to mostly pines for Boletus edulis, a whitish bloom in youth, and a more equal stipe at maturity. Boletus edulis differs additionally in having a cap margin that slightly overlaps the tube layer.

For many years this species was identified as the European species Boletus aereus (Thiers 1975, Arora 1986, Bessette et al. 2000). It was formally described as a distinct species, Boletus regineus, based on a California type collection (Arora 2008).

Common names: Queen Bolete.

Mushroom Identification

1. Cap

   Up to 20 cm, convex, expanding to plano-convex; margin incurved, later decurved to nearly plane, not overlapping the tube layer; surface moist, more or less glabrous when young, becoming irregularly pitted or wrinkled; color at first unevenly buff-brown to pale chestnut-brown, overlain initially with a whitish bloom, in age becoming medium-brown to dark-brown, subviscid when moist; context up to 2 cm thick white, unchanging, firm in youth, soft at maturity, tinged pinkish-vinaceous below the cuticle, sometimes yellowish above the tube layer; odor and taste mild.

2. Hymenophore

   Pores up to 3/mm when young, stuffed, approximately 1/mm in age, whitish, becoming cream-colored to dull pale-yellow, eventually dingy yellowish-olive, not bluing, darkening slightly where handled; tubes up to 2 cm long, occasionally discoloring brownish when cut, not bluing, depressed at the stipe.

3. Stem

   5-17 cm long, 3-6 cm thick, solid, clavate to ventricose in youth, subclavate to equal at maturity; the surface of apex reticulate, whitish, elsewhere glabrous to faintly wrinkled; the context of the stipe, not bluing, but darkening slightly when cut; partial veil absent.

4. Spores

   11.5-13.5 x 3.5-4.5 µm, smooth, thin-walled, narrowly ellipsoid in face-view, hilar appendage inconspicuous, one to several guttules.

5. Spore Print

   Dull olive-brown.

6. Habitat

   Solitary to scattered in mixed hardwood/conifer forests; fruiting shortly after the fall rains.

Look-Alikes

1. Boletus appendiculatus

   Another edible, robust bolete found in mixed woods. This rusty-brown to yellowish-brown capped bolete gets its common name from a yellowish, often reticulate stipe, and yellow pores that blue rapidly when bruised.

2. Boletus pseudoregius

   Is somewhat similar, but it has dull pink to pinkish brown cap, yellow blueing flesh, blueing tubes and pores, and spores of different sizes.

3. Boletus kluzakii

   May have similarly colored fruitbodies but it has blueing flesh and bitter taste.

Photo sources:

Photo 1 - Author: J. Maughn (Attribution-NonCommercial 2.0 Generic)

Photo 2 - Author: J. Maughn (Attribution-NonCommercial 2.0 Generic)