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Summary: Features include 1) a dull cinnamon to orange-brown or yellowish cap that is viscid, appressed-fibrillose and somewhat streaked, sometimes with hanging veil remnants on margin, 2) cap flesh that is yellow staining pinkish, the stem flesh yellow staining blue-green in the base and vinaceous brown elsewhere, 3) large angular to irregular pores that are often radially arranged, the pores yellow to ocher bruising dingy vinaceous brown, 4) stem that is yellow above the whitish fibrillose band-like annulus and dull ocher-brown appressed-fibrillose below it (staining brown when bruised or sometimes blue near base), the stem lacking glandular dots but often weakly reticulate at top, and 5) growth under conifers, particularly Douglas-fir. Suillus caerulescens is found from the Rocky Mountains to the Pacific Northwest, (Bessette), only in Pacific Northwest and CA, (Arora), in WA, OR, and CA, (Smith(34)), in ID (Smith(36)), in BC (in Redhead), and in MT (L. Evans, pers. comm.).
Cap: 6-14cm, obtuse to convex, becoming broadly convex to nearly flat; "ochraceous tawny, reddish brown to pale yellow-brown or tan, typically yellowish toward the margin, sometimes with dark green stains"; "viscid to moist when fresh, appressed-fibrillose and somewhat streaked", becoming bald when old; margin often appendiculate [with hanging veil remnants], (Bessette), 6-14cm, broadly and shallowly convex becoming flat-convex to nearly flat or flat; color varying from uniformly dull "vinaceous" to "ochraceous tawny" on disc and yellow toward margin ("ochraceous buff"), or more dingy, squamules near margin sometimes colored near "cinnamon" (colors in quotation marks from Ridgway); "viscid but not truly glutinous and occasionally appearing only moist, usually with patches of agglutinated fibrillose tomentum which appears as scattered squamules or streaks", often appearing bald when old; margin at times appendiculate, (Smith(34)), "dull cinnamon to yellowish, but most often dull reddish-brown, orange-brown, or yellow-brown toward the center and yellowish to buff near the margin, with dingy greenish stains sometimes developing in cold weather", (Arora)
Flesh: pale yellow, sometimes staining pinkish when cut, in stem yellow and staining bluish green in base when exposed, (Bessette), 1-2cm thick, pale yellow, unchanging or assuming a dingy pinkish flush; in stem yellow, slowly staining blue in base when cut, elsewhere discoloring vinaceous brown, (Smith(34))
Pores: about 1mm, angular to irregular, often radially arranged; yellow to pale ocher at first, darkening when old, "slowly staining dingy vinaceous brown when bruised"; tube layer 0.6-1cm, adnate to subdecurrent, (Bessette), 1.5-2mm broad radially, about 1mm wide, very irregularly angular and uneven from the irregular configuration of the walls, sometimes radially aligned but not always, occasionally appearing compound, pores yellow ("honey yellow"); tube layer 0.6-1cm thick, adnate to short decurrent, "primrose yellow" to "sulfur yellow" to "deep colonial buff" (colors from Ridgway), when old extensively discolored dingy vinaceous brown from bruising, (Smith(34))
Stem: 2.5-8cm x 2-3cm, narrowing in either direction or nearly equal, solid; dull ocher-brown, staining brown when bruised, yellow above annulus; dry, appressed-fibrillose from base up to annulus, often weakly reticulate at top, lacking glandular dots; "partial veil dry, fibrillose, whitish, leaving an uneven superior annulus", (Bessette), 2.5-8cm x 2-3cm at top, narrowing toward the top or base or equal, solid; colored the same as the tubes above the annulus, duller and often dingy brown below annulus, stem staining brown where handled; reticulate at top from decurrent tubes, bald to furfuraceous-punctate above annulus, bald to appressed-fibrillose to dull and matted-fibrillose below annulus, no glandular dots; annulus band-like, fibrillose, pallid to white but soon discoloring as cap, not gelatinous, (Smith(34)), slight to distinct superior or median annulus that is fibrillose to band-like and whitish becoming colored like cap when old, stem yellow above the annulus, fibrillose and dingier below the annulus and often mottled with reddish or brown stains and usually staining brownish after handling, stem sometimes spotted but not glandular dotted, (Arora), stem base bruising blue when handled, (Phillips)
Odor: not distinctive (Bessette), mild or slightly acidulous (Smith(34)), none or slightly sour, (Phillips)
Taste: not distinctive (Bessette), mild or slightly acidulous (Smith(34)), none or slightly sour, (Phillips)
Microscopic: spores 8-11 x 3-5 microns, elliptic, smooth, colorless to ochraceous, (Bessette), spores 8-11 x 3-5 microns, elliptic, smooth, pale orange-buff to cinnamon-buff in Melzer's reagent, colorless to ochraceous in KOH; basidia 4-spored, 20-30 x 5-8 microns, clavate, yellowish in KOH and Melzer's reagent; pleurocystidia of 2 types: 1) cylindric to clavate with brown pigment around base of cluster, 35-70 x 5-8 microns, content brown to colorless in KOH, 2) fusoid-ventricose and isolated to scattered, 22-28 x 5-8 microns, with refractive granules, cheilocystidia in clusters and 60-100 x 5-9 microns, cylindric to clavate or narrowly fusoid-ventricose, colorless to yellow-brown; cap epicutis a collapsed trichodermium with elements 8-17 microns wide, and a basal layer with elements mostly unbranched and 3-7 microns wide and colorless to pale ochraceous in KOH, the layer gelatinous and up to 400 microns thick; tube trama with numerous large contorted laticifers present, cap flesh with occasional laticifers; caulocystidia similar to cheilocystidia (in clusters and with pigment at base of cluster) occurring only at the annulus level; clamp connections absent, (Smith(34))
scattered or in groups on ground or among mosses under conifers, (Bessette), scattered to densely gregarious on ground under or near Douglas-fir, (Arora), mostly under mixtures of Douglas-fir, lowland fir, hemlock and redwood, with larch present at times, (Smith(34)), confined to Douglas-fir (Thiers), summer, fall, winter
Suillus ponderosus differs in having a viscid yellow to orange veil (before breaking) and a smoother, viscid to slimy cap, (Arora). S. ponderosus has a veil that is glutinous on the undersurface, (Smith(34)). Suillus lakei lacks the distinct blue change in the flesh of the stem base, and lacks the numerous laticiferous ducts in the tube trama, (Smith(34)). S. lakei has a fibrillose to floccose-scaly cap and the flesh of the stem base stains weakly blue-green or not at all, (Bessette). Suillus imitatus is bald, has smaller spores, and lacks laticiferous ducts in tissues, (Smith(34)). S. imitatus has a cinnamon to reddish cinnamon bald cap whereas S. caerulescens is paler with scattered fibrils or streaked with gluten, (Thiers). Suillus imitatus var. viridans may be confused and has similar spores but is bald, (Bessette).
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2020. E-Flora BC:
Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for
Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
2020-07-09 6:09:44 PM
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