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Species Information
Summary: Features include small size, a buff to brown dry cap, somewhat crowded gills, growth on Sitka spruce cones, spores that are small, smooth, and inamyloid, and thick-walled pleurocystidia capped with an apical resinous mass.
Strobilurus occidentalis has been reported from at least BC, AB, AK, CA, and CO, (Redhead(1)). There are collections from western WA on spruce cones and a collection from western OR on Sitka spruce cones at the University of Washington.
Cap: 0.3-1.5cm across, convex, at times somewhat umbonate, becoming flat-convex; somewhat hygrophanous to not hygrophanous, deep yellow brown to dark yellow brown or vinaceous buff, hazel or grayish sepia; dry, smooth to rugulose [finely wrinkled], margin striate when old, (Redhead(1)), 0.6-1.6cm across, convex or flat-convex; grayish yellow or pale yellowish gray overall when young, when old disc brownish gray, margin orange gray to buff, or often buff overall when mature (pinkish tones absent); bald, smooth or subrugulose [somewhat wrinkled], dull, translucent-striate, (Desjardin), nearly white if heavily shaded, otherwise tan to medium or dark gray-brown, margins often paler, (Lennox)
Gills: adnate to adnexed, crowded to subcrowded, 2 to 3 tiers of subgills, moderately broad; white, (Redhead(1)), adnexed, close or subdistant, 2-3 tiers of subgills, moderately broad; white, (Desjardin), "narrowly adnate, sinuate, to almost free", (Lennox)
Stem: 1-5cm x 0.1-0.2cm, equal, "somewhat cartilaginous to horny", stuffed, becoming hollow when old, root-like pseudorhiza "usually present, up to 6cm long, covered with a dense ochreous floccose mycelium"; stem white at top, cinnamon to umber in lower part; pruinose to nearly bald, (Redhead(1)), 2.5-5cm x 0.075-0.15cm, equal, round in cross-section, with short root-like pseudorhiza; top white, mid-part grayish orange, base brownish orange; top pruinose, mid-part pubescent [downy], base tomentose, covered with downy, orange or ochraceous mycelium, (Desjardin), orange-brown over lower parts with a white apex, darkening when old, (Siegel)
Odor: not distinctive (Desjardin), none or slightly of radish (Lennox)
Taste: not distinctive (Desjardin)
Microscopic spores: spores 4-6 x 2-3 microns, elliptic to cylindric, thin-walled, smooth, colorless, inamyloid; basidia 4-spored, 15-20 x 3-5 microns, clavate, simple-septate; pleurocystidia and cheilocystidia rare to abundant, 35-45 x 6-12 microns, "obtusely ventricose to fusoid-ventricose or rarely capitate when walls excessively thickened", colorless, "capped by a massive resinous and granular excretion", "walls thin to thick, up to 2-3.5 microns thick, often thinning apically"; pileocystidia scattered, infrequent, 20-30 x 9-10 microns, tapering in upper part to just below a capitate top, colorless, smooth; caulocystidia abundant, similar to pileocystidia, 40-95 x 10-13 microns, sometimes somewhat conic, mostly capitate, occasionally aggregated, (Redhead(1)), no clamp connections on cap surface hyphae, (Lennox), spores 4.2-6 x 2.4-3 microns, elliptic or subamygdaliform [somewhat almond-shaped]; basidia 4-spored, 16.8-22.8 x 3-4.5 microns, clavate; pleurocystidia abundant, 33-45 x 9.6-14.4 microns, "obclavate or fusoid-ventricose, rarely subcapitate, capped with a large, globose, granular and resinous mass", walls 1-3 microns thick, colorless to pale yellow, and inamyloid, cheilocystidia abundant, 32.4-42 x 4.8-8.1 microns, cylindric, "subcapitulate or narrowly fusoid-ventricose, subcapitate or not, lacking an apical resinous mass", walls up to 1 micron thick, colorless or pale yellow, and inamyloid; cap cuticle hymeniform, cells 12-30 x 6-18 microns, broadly clavate, spheropedunculate, pyriform, or irregular in shape, with scattered pileocystidia 24-42 x 5.4-10.8 microns, "ventricose-rostrate or cylindric-subcapitate", colorless or pale yellow, thin-walled; caulocystidia "abundant, scattered or clustered", 32-120 x 7.2-18 microns, "ventricose-rostrate with a capitate rostrum or narrowly conic-capitate", walls up to 2 microns thick, colorless or pale ochraceous, inamyloid, (Desjardin)
Spore deposit: white (Redhead(1))
Habitat / Range
on "buried or exposed senescent cones or cone scales" of Picea sitchensis (Sitka spruce); "in coastal flood plains, boreal forest, or subalpine forest, sometimes near melting snow banks", (Redhead(1)), scattered to gregarious on senescent cones of Picea sitchensis (Sitka spruce), in mixed coniferous woods, October to December, (Desjardin for coastal northern California), on old cones (sometimes buried), cone bracts, and needles of pine, spruce, and Douglas fir, leaf stems of poplar, (Schalkwijk-Barendsen), in dense conifer woods, on buried wood or cones of Picea sitchensis (Sitka Spruce) and Picea glauca (White Spruce), mostly 1 but sometimes 2-3 fruitbodies per cone, early spring or late fall, (Lennox), spring, fall, winter
Similar Species
Strobilurus trullisatus is generally on Douglas-fir cones, has a pink cast, and differs microscopically (thinner-walled pleurocystidia with apical collarettes), (Desjardin). S. trullisatus is more common on Douglas-fir cones but can occur on Sitka spruce cones - it has a paler cap and a yellowish to yellow-grown stem with a white apex, (Siegel(2)), S. trullisatus has a whitish cap often with pink tones, favors Douglas-fir cones, and has "pleurocystidia whose tips usually bear a mass of granular material that leaves a bit of a ridge when it disappears", (Trudell). |Strobilurus albipilatus 1) has its immature cap typically dark grayish brown, 2) fruits on woody debris, rarely cones of Pinus, [according to Redhead also cones of Pseudotsuga menziesii], (whereas S. occidentalis has a particular affinity for Sitka spruce cones), and 3) has pleurocystidia that are cylindric or capitulate, thin-walled, and rarely capped with a granular and resinous mass, whereas pleurocystidia of S. occidentalis are obclavate or fusoid-ventricose (rarely subcapitate), thick-walled, and capped with a large, spherical, granular and resinous mass, (Desjardin). |Baeospora myosura has crowded gills, weakly amyloid spores, clamp connections, and a cap cuticle composed of repent, radially oriented filamentous hyphae, (Desjardin). B. myosura has even more crowded gills and smaller (3-4.5 x 2-3 microns), weakly amyloid spores, a "cap cuticle with mostly thin, flat-lying hyphae", and clamp connections, (Trudell). |Strobilurus wyomingensis (subalpine habitats of ID, WY, CO), could be a variety of S. occidentalis and is closely related genetically - it usually has larger fruitbodies and spores ((5)5.5-8(9.5) x 3.0-5(6) microns versus 4-5.5(6.5) x (2)2.5-3(4) for S. occidentalis), (Qin(1)).
