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

Butyriboletus persolidus (Schaeffer) D. Arora & J.L. Frank
no common name

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

Introduction to the Macrofungi
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Distribution of Butyriboletus persolidus
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Species Information

Features include 1) almost bald cap that varies from reddish brown to cinnamon brown to yellow-brown to yellowish or buff, 2) dense flesh with mild taste, 3) yellow pores that usually bruise blue quickly, and 4) finely netted yellow stem. RANGE This species has been confirmed only from CA where it occurs "in both the coastal region and in the Sierra Nevada foothills" (Arora(3)). It has been known as Boletus appendiculatus (Schaeff.) Secr. sensu Theirs. Arora(3) comment "Reports of Boletus appendiculatus sensu Thiers under conifers in the Pacific Northwest (e.g. Tylutki 1987) appear to be misidentifications based on Butyriboletus abieticola, Bu. primiregius and/or Bu. autumniregius. However, reports of Boletus appendiculatus with Q. garryana on Vancouver Island, British Columbia, are likely based on either this species and/or Bu. querciregius.", (Arora(3), with Latin names italicized). A collection from BC (as Boletus appendiculatus) is at the University of British Columbia.
6-13cm, convex to spherical when young, becoming flat to flat-convex to shallowly depressed on disc, often highly irregular and uneven, margin incurved when young becoming broadly downcurved; buff to pale yellow when young, dull yellow to pale brown when older, often with stains or appearing overlaid with rust to red-colored blushes, occasionally with dark brown areas; dry to occasionally subviscid when wet, dull, bald to obscurely tomentose or velvety, sometimes shallowly cracked to areolate [cracked like dried mud] when old , (Thiers), 6-20cm, cushion-shaped to convex, becoming broadly convex to nearly flat when old, margin incurved at first and typically with narrow band of sterile tissue; "reddish brown to rusty brown or yellow-brown, sometimes pale to dull yellow, when young", dry, bald or nearly so, (Bessette), 6-20(30)cm, smooth or with a fine bloom when young, (Arora(1))
1-3cm thick, pale yellow to yellow, "unchanging or slowly changing to blue when exposed", in stem yellow near surface, whitish in center, unchanging or turning slightly blue in irregularly distributed areas when exposed , (Thiers), firm and dense; "pale yellow to yellow, not staining or slowly and erratically blueing when exposed", (Bessette), flesh in base usually pinkish or vinaceous (Arora(1))
up to 1 mm broad, angular; yellow becoming dark yellow, turning blue when bruised; tube layer 1-2cm thick, deeply and broadly to narrowly depressed , (Thiers), 1-3 per mm, angular; pale yellow becoming yellow to dark yellow or olive-yellow, turning blue when bruised; tube layer 0.8-2cm thick, depressed near stem when old, (Bessette), usually turning blue when bruised, but sometimes not (especially in button stage), (Arora(1))
6-9cm x 2-4cm, typically bulbous to wider in middle, sometimes equal, solid, occasionally with root-like prolongation; yellow, often with vinaceous to reddish brown stains, reticulation yellow or sometimes vinaceous to reddish; dry, reticulate [with a network] for two thirds of length , (Thiers), 5-14cm x 2-5cm, bulbous or wider in middle or sometimes equal, solid; yellow with reddish brown stains especially near base; dry, with a fine inconspicuous reticulation [network] on upper part, (Bessette), 5-15cm x 2-6cm, (Arora(1))
Chemical Reactions:
flesh pale vinaceous with KOH, (Thiers, Bessette)
not distinctive (Thiers, Bessette)
not distinctive (Thiers, Bessette)
spores (10)12-14(16) x 4-5(6) microns, subfusoid [somewhat spindle-shaped] to subcylindric [somewhat cylindric], smooth, individual spores brown in Melzer's, amyloid in mass, pale ochraceous in KOH, thin-walled ; basidia 4-spored, 26-31 x 9-12 microns, clavate, colorless; hymenial cystidia 48-65 x 8-13 microns, fusoid-ventricose, colorless, thin-walled; cap cuticle differentiated as a trichodermium of interwoven to tangled hyphae, pale brown in KOH, not incrusted; stem cuticle fertile on ridges, interwoven in other parts; clamp connections absent, (Thiers), spores 12-16 x 4-6 microns, somewhat cylindric to somewhat fusoid, smooth, ochraceous, (Bessette), spores 12-15 x 3.5-5 microns (Arora(1))
Spore Deposit:
dark olive brown (Thiers), olive brown (Bessette)

Habitat / Range

single to gregarious under hardwoods , (Thiers), single, scattered, or in groups on ground under oak, September to January, (Bessette), fall, winter

Synonyms and Alternate Names

Boletus appendiculatus (Schaeff.) Secr. sensu Thiers California Mushrooms: A Field Guide to the Boletes: 41. 1975

Taxonomic and Nomenclatural Links

Additional Range and Status Information Links


yes, considered choice by some, but because of taxonomic confusion, use restraint, (Thiers) , yes, considered choice by some, (Bessette), some people are "allergic" to it (Arora(1))

Additional Photo Sources

Related Databases

Species References

Thiers(1) (as Boletus appendiculatus), Bessette(3)* (as Boletus appendiculatus), Arora(1)* (as Boletus appendiculatus), Both(1) (as Boletus appendiculatus), AroraPocket* (as Boletus appendiculatus), Arora(3)

References for the fungi

General References