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

Summary:
Features include a whitish to tan or brown or violet-gray cap that is bumpy and/or pitted, cap flesh with blue lines, stem flesh blue to purple black, teeth that are whitish to grayish brown, a stem that is grayish blue to bluish black and usually has a swollen rooting base, and a fragrant anise or peppermint odor. It is especially common in the Rocky Mountains.

The distribution includes NM to BC in the west, along the Appalachians from NC into Canada in the east, and reportedly also MI, (Harrison). It is also reported from WA (Hall), ID and NM, (Arora), CA (Desjardin), and NS, PQ, CO, ME, NC, and WY, (Coker). The University of Washington has collections from WA, OR, ID, and AK.

Cap:
(3)5-15(30)cm when mature, top-shaped becoming flat to somewhat depressed, often with needles and other debris incorporated; white at first, "soon becoming yellowish to tan, brownish, olive-brown, or violet-gray from center outward (margin often paler), usually staining brown where bruised"; "thinly felty or velvety at first", often bumpy and/or pitted when old, (Arora), often top-shaped with irregularly rounded cap, 3-10cm, whitish, sometimes with bluish tint, then turning dark brown, zoned, margin whitish for a long time; undulating, tuberculate, radially wrinkled, often with scaly outgrowths, velvety when young, then fibrillose and bald, margin irregularly crenate [scalloped] for a long time, (Breitenbach), (3.6)6-12(14)cm, somewhat round in outline or lobed, at times confluent, convex then flat; margin thick or thin, more or less uneven; white at first (and remaining so at margin until old), then tan-brown which may be faintly tinted with violet, fawn, smoky-gray, or olive; azonate, colliculose, softly felted, the felt collapsing from center outward to leave smooth soft surface, (Coker), flat to funnel-shaped (Hall), "sordid white changing slowly to snuff-brown at center and gradually outwards to the white margin", (Harrison), usually "yellowish brown with a whitish or very pale blue edge", (Trudell)

Flesh:
duplex, whitish to yellowish buff zoned with blue lines in cap; in stem "entirely deep blue to purple-black", (Arora), corky and tough; whitish-bluish, with distinct blue and brownish zones, (Breitenbach), thick or moderately thin, not obviously duplex but soft in upper part and gradually harder downward, "conspicuously zoned vertically with soaked drab and white layers, the drab becoming blue or greenish, especially downward, on exposure"; in stem strongly and closely zoned with deep blue, even when freshly cut, (Coker), fibrous, thin to thick; zoned with violet - brightest in stem, (Harrison)

Teeth:
up to 0.3cm long, irregularly decurrent; whitish to cream when young, becoming grayish brown with pallid tips when old, (Arora), up to 0.5cm long, 0.03cm wide, simple to multiply branched; whitish bluish when young, then brown with ocherish tips, (Breitenbach), up to 0.7cm long, crowded, often decurrent far down the stem, at times even to substrate; pale drab then drab brown with pale tips, (Coker), pale to dark vinaceous brown (Harrison)

Stem:
1-5cm x 1-3cm, "central or slightly off-center, very tough, base usually swollen, rooting"; grayish blue to bluish black, (Arora), 1.5-5cm x 1-3cm, cylindric to conic, solid; gray-blue to blackish, (Breitenbach), about 1-2cm long and up to 1.5cm wide, central or off-center, firm, solid; deep indigo blue or blackish or blue-black; mycelium deep blue, (Coker), tomentose with a bright violet shade that darkens on being rubbed; fades to pallid, (Harrison)

Chemical Reactions:
velvety layer on stem stains blue-green with KOH (McKnight), KOH stained the violet tomentum on stem a blue-green and a trace of that shade appeared when colored flesh tested, (Harrison)

Odor:
"often strongly fragrant (like anise or peppermint)", sometimes absent (Arora), pleasantly anise-like or coumarin-like, pronounced, (Breitenbach), "variable in intensity, faint when first collected but after a few hours usually distinctly aromatic as of wintergreen or peppermint and persisting for many years", (Coker), coumarin or anisealdehyde (Hall), strong, sweet or sickly, (Phillips), strongly fragrant (sickening-sweetish), (Harrison)

Taste:
mild to somewhat bitter, (Breitenbach), none (Coker), mild to slightly cinnamon-like (Phillips), mild or slightly cinnamon-like (Harrison)

Microscopic:
spores 4-6 x 3-4 microns, elliptic to nearly round, prominently warted, (Arora), 3.5-5 x 2-3.5 microns, irregularly polygonal with indistinct tubercles, inamyloid; basidia 4-spored, 18-28 x 3-4 microns, slenderly clavate, with basal clamp connection; cystidia not seen; hyphae monomitic, hyphae in subhymenium and cap trama 2.5-5 microns wide, branched; septa with clamp connections, (Breitenbach), 3.8-5 x 3-3.7(4.2) microns, nearly round to elongated, irregularly and bluntly tuberculate; basidia 4-spored, 4.8-5.5 microns wide; hyphae of context pale, thin-walled, intricately and rather loosely interwoven in upper part, more nearly parallel in firmer part, "occasionally branched and septate, with conspicuous clamp connections", (Coker), spores 4.5-6 x 3.0-4.0 microns, (Hall), in water strands of dark blue hyphae present in context, these hyphae turning greenish in KOH, and then slowly fading, and in Melzer''s reagent the hyphae are incrusted with very fine granular material that gives them an apparent amyloid appearance, hyphae in teeth 3-4 microns wide, parallel, clamped, and with fine incrusting apparent amyloid granules, (Harrison)

Spore Deposit:
brown (Arora), vinaceous brown (Harrison)