Summary:
Features include 1) large size, 2) an orange-red cap that is bald or nearly so, 3) white unchanging cap flesh, 4) whitish to pale olive brown pores that bruise yellow-brown, 5) a stem with brown to blackish scabers that stains blue especially toward base, 6) growth under conifers, and 7) microscopic characters including orange-brown pigment globules in the cap cuticle hyphae in Melzer''s reagent.

Odor:
not distinctive (Bessette)

Taste:
not distinctive (Bessette)

Microscopic:
spores 14-17 x 4.5-6 microns, fusoid [spindle-shaped], smooth, ochraceous, (Bessette), spores 14-17 x 4.5-6 microns, hyphae of cap cuticle 4-12 microns wide, in Melzer''s reagent "the content rounding into distinct globules in some"; caulocystidia mostly clavate, (Smith(4)), spores 14-17 x 4.5-5.5(6) microns, fusoid [spindle-shaped], smooth, tan in Melzer''s reagent, ochraceous in KOH; basidia 4-spored, 18-24 x 9-12 microns, often with a large colorless globule; pleurocystidia "36-45 x 8-13 microns, fusoid-ventricose with neck often irregular, apices acute to subacute", content colorless or brownish, cheilocystidia 20-32 x 7-12 microns, clavate to clavate-mucronate, ochraceous in KOH; caulocystidia (30)40-70 x (8)10-18 microns, mostly clavate, content smoky ochraceous in KOH; cap cutis with hyphae of epicutis 4-12 microns wide, "the end-cells not distinctively differentiated (at most merely somewhat cystidioid), walls smooth or very rarely minutely asperulate, cells readily disarticulating, cells mostly more than 5 times longer than wide, content brownish in KOH and pigment separating in rather indistinct globules, in Melzer''s with large medium and small pigment globules red to orange-red in color"; hyphae of context near subcutis with yellow to orange content when revived in Melzer''s reagent; clamp connections none, (Smith(38))

Spore Deposit:
brown (Bessette)

Notes:
Leccinum ponderosum is found in WA, OR, and ID, (Bessette). It appears on foray lists from BC.

EDIBILITY

reported by some authors including Bessette(3) as edible, but orange Leccinum species have been implicated in poisoning episodes

Synonyms and Alternate Names:
Boletellus mirabilis (Murrill) Singer Farlowia 0.0833333333333333 129 1945
Boletus mirabilis (Murrill) Murrill