Summary:
Features include 1) a nearly black cap with a whitish bloom and a smooth or somewhat pitted surface, 2) white to vinaceous-tinged, unchanging flesh, 3) small angular pores that are white becoming yellowish and do not turn blue, 4) club-shaped to equal, reticulate stem that is white and may become vinaceous brown, 5) growth under hardwoods or conifers, and 6) microscopic characters. Boletus regineus was known for many years on the west coast of North America as Boletus aereus Bull. The taxon of CA, OR, and WA was redescribed in 2008 as Boletus regineus D. Arora and Simonini. The authors noted that the gelatinized pileipellis clearly distinguished it from European B. aereus, which has a dry, velvety cap cuticle with a non-gelatinized trichoderm of subparallel hyphae, and a browner stem, (Arora(2)). Boletus mottiae Thiers, California Mushrooms p.36. 1975 is said to be a "mutated" collection of Boletus regineus.

Chemical Reactions:
flesh does not stain with application of KOH or FeSO4, (Bessette)

Odor:
mild (Arora(2)), mild (Thiers)

Taste:
mild (Arora(2)), mild or pleasant (Arora(1)), mild (Thiers)

Microscopic:
spores (11.5)12-15(17) x (3.9)4-4.7(5.4) microns, "variable in shape and dimensions, long ellipsoid-fusiform"; basidia clavate, colorless, mostly 4-spored, 23-40 x 8-11.5 microns; hymenial cystidia thin-walled, inconspicuous; cap cuticle "a completely gelatinized cutis when mature (and sometimes even in youth)", typically 200-250 microns thick, cuticular cells 7-10 microns wide, "variable in shape, sometimes branched or with diverticula", (Arora(2)), spores 12-14 x 4-5 microns, spindle-shaped to elliptic, smooth, (Arora(1)), spores 12-13.5 x 4-5 microns, subelliptic to subfusoid, smooth, pale ochraceous in KOH and Melzer''s, thin-walled; basidia 4-spored, 23-30 x 8-10 microns, colorless in KOH; hymenial cystidia inconspicuous, embedded in hymenium, 28-34 x 7-11 microns, colorless in KOH and Melzer''s, thin-walled; cap cuticle "a broad (175 microns) trichodermium of erect, septate hyphal tips, terminal cells not enlarged, not incrusted, hyaline in KOH, pale ochraceous in Melzer''s, hyphae 4-5 microns wide"; clamp connections absent, (Thiers)

Spore Deposit:
"olive-brown in mass, but yellower than closely related species under the microscope", (Arora(2)), dark olive-brown (Arora(1), Thiers)

Notes:
Collections of Boletus regineus were examined from CA where it is fairly common, but distribution in OR and WA is also mentioned (Arora(2)). It has been reported as Boletus aereus from OR (H. Thiers 1986, pers. comm. to L. Norvell, Dick Bishop pers. comm.), WA (J. Lindgren pers. comm., M. Beug pers. comm., collection at the University of Washington as B. aereus), and BC (O. Ceska pers. comm.). A collection from OR was used in Arora(3).

EDIBILITY

delicious (Arora(1), Arora(2), Thiers)

Synonyms and Alternate Names:
Clavaria cristata Fr.
Clavulina cristata (Fr.) J. Schroet.