E-Flora BC: Electronic Atlas of the Flora of British Columbia

Leccinum ponderosum A.H. Sm., Thiers, and Watling
no common name

Species account author: Ian Gibson.
Extracted from Matchmaker: Mushrooms of the Pacific Northwest.

Introduction to the Macrofungi

© Jim Riley  Email the photographer   (Photo ID #52542)

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Distribution of Leccinum ponderosum
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Species Information

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.

Leccinum ponderosum is found in WA, OR, and ID, (Bessette). It appears on foray lists from BC.
9-30cm, convex, becoming broadly convex to nearly flat when old; orange-red to dull brick-red; dry, bald or nearly so; margin "with thin flaps of sterile tissue at least when young", (Bessette), 10-30cm, ferruginous-red; soon viscid, (Smith(4)), 10-30cm, obtuse to convex when young, with appendiculate margin, expanding to broadly convex to nearly flat; ferruginous red ("Kaiser-brown" to "vinaceous-rufous" or "rufous") and when dried dull brick red; subviscid when young, more viscid when old, bald to appressed-fibrillose, (Smith(38))
"white, not staining when exposed or bruised", (Bessette), white, when cut not changing appreciably, (Smith(4)), "white when cut and not changing appreciably, but as dried mostly merely buff-color throughout pileus and stipe but with a few gray streaks", (Smith(38))
2-3 per mm, round to angular; whitish at first, becoming dingy whitish to pale olive brown when old, "slowly staining yellowish to orange-brown when bruised"; tube layer 0.8-2cm thick, typically depressed near stem when old, (Bessette), "young pores pallid to avellaneous", staining ochraceous where lightly bruised; tube layer 1-2cm thick, pallid, (Smith(4)), minute; "pallid to avellaneous when young, staining ochraceous where lightly bruised"; tube layer 1-2cm thick (in young caps), "adnate-subdecurrent, dingy clay color as dried", (Smith(38))
7-15cm x 2-3cm, widening downward, solid; "whitish, with brown to fuscous scabers, staining blue when bruised, especially toward the base"; dry; partial veil and annulus absent, (Bessette), 8-16cm x 2-3cm at top, enlarging to 5-9cm at base, solid, hard; apex pale buff, when fresh often flushed reddish like the cap, stem "where handled staining blue (entire base finally) and in drying becoming yellow to olive-yellow"; "with avellaneous to fuscous points and squamules arising from a pallid cottony rather well-developed under-layer", ''the ornamentation drying near "snuff brown" and appearing as irregular patches of appressed material'', (Smith(38))
not distinctive (Bessette)
not distinctive (Bessette)
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)

Habitat / Range

single, scattered or in groups on or near decaying conifers, especially pines, (Bessette), scattered under Ponderosa or Lodgepole Pine, (Smith(4)), type under Pinus ponderosa and P. lambertiana (Smith(38)), fall

Synonyms and Alternate Names

Boletellus mirabilis (Murrill) Singer Farlowia 0.0833333333333333 129 1945
Boletus mirabilis (Murrill) Murrill

Taxonomic and Nomenclatural Links

Additional Range and Status Information Links


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

Additional Photo Sources

Related Databases

Species References

Smith(38) (colors in quotation marks from Ridgway), Bessette(3)*, Smith(4), Thiers(1), Both(1)

References for the fungi

General References