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

Summary:
Features of Suillus tomentosus include 1) a dry to viscid cap that has grayish brown to ocher, olive-yellow or reddish brown fibrils or scales on yellow to orange yellow background, 2) pallid to yellow flesh that turns blue, 3) brown then yellow pores that turn blue when bruised, 4) stem the same color as the cap or more orange, with glandular dots on stem that are usually browner, and no partial veil or annulus, and 5) growth under conifers, particularly 2-needle pines. The fruiting body tends to stain the fingers brown. S. tomentosus is very common in the Pacific Northwest.

It is found in WA, OR, ID, CA, CO, MI, WY, (Smith(34)), NB, NS, PQ, and NC, (Both). It is widely distributed from eastern Canada south to NC and SC, west to the Pacific Northwest, south to CA, (Bessette). It has been reported from BC (Bandoni), and MT (L. Evans, pers. comm.). Var. discolor occurs in ID.

Cap:
5-12cm, obtuse to convex, becoming broadly convex to flat when old and margin uplifted and wavy; yellow to orange-yellow ground color, fibrils and scales grayish, yellow-ocher, dark olive-yellow, or reddish brown; conspicuously fibrillose-scaly when young, becoming nearly bald when old; margin coarsely tomentose at first, (Bessette), 5-10(15)cm, obtuse to convex, becoming broadly convex; ground color pale yellow to pale orange-yellow, with tomentum and scales that vary ''from pallid (young buttons) to pale buff, pinkish buff, grayish (when wet), orange-cinnamon to tawny, russet, or "Bordeaux red" (dark red)'' (Ridgway colors); viscid beneath tomentum and scales, at first tomentose-floccose to squamulose but gradually becoming bald; margin rather coarsely tomentose at first but gradually becoming bald, (Smith), 5-15(20)cm, "background usually pale yellow to yellow-orange, orange-buff, or dark dull orange", "fibrils or scales usually grayish brown to brown (reddish in one form), sometimes pallid or buff when young"; dry, but in wet weather or when old often viscid, at first covered with a dense coating of fibrils that break up to form scattered scales and are often sparse or even absent when old, (Arora), velvety to soft-scaly; margin extends beyond tubes (McKnight), "typically has a covering of grayish, yellowish, reddish brown, or bright red fibrils or fibrillose scales over an orange-yellow to yellowish background", (Trudell)

Flesh:
"yellow, staining blue irregularly and often slowly when exposed", (Bessette), 0.8-1.5cm; pallid to yellow but paler than cap surface, "changing slowly to blue or greenish blue when cut or bruised"; in stem yellow but paler than cap surface, staining greenish blue slightly when cut, (Smith)

Pores:
up to 1mm, angular; "brown to vinaceous brown or dingy cinnamon", becoming dingy yellow to olive-yellow when old, turning blue when bruised; "sometimes beaded with yellowish droplets at first"; tube layer 0.8-1.5cm thick, adnate to subdecurrent, (Bessette), about 2 per mm, bister to dark dingy cinnamon or vinaceous brown when young, slowly becoming dingy yellow, staining bluish when injured at least when old; tube layer 1-2cm thick, adnate to decurrent, rarely depressed around stem, "pale dingy yellow becoming dingy olive-yellow and staining dingy greenish blue when injured", (Smith), usually turning blue at least slightly when bruised, at least when old, (Arora)

Stem:
5-12cm x 1-2.5cm, widening downward or nearly equal, solid; yellow to dull orange-yellow; with darker orange to brownish glandular dots, dry to moist; partial veil and annulus absent, (Bessette), (3)5-10(12)cm x 1-2(3)cm at top, equal or clavate, solid; colored as cap or more orange, when tomentum is reddish on cap, the base of the stem may be reddish also; "glandular-dotted to glandular-punctate over all"; no veil remnants; mycelium around base cream to cream-buff at first, soon becoming vinaceous-buff or redder, (Smith), 3-11(15)cm x 1-3cm, dots may be the same color as stem or browner and are often obvious when old; base sometimes reddish-stained, (Arora)

Chemical Reactions:
cap surface stains pale gray with application of FeSO4, (Bessette), flesh pale gray with FeSO4, (Thiers)

Odor:
not distinctive (Bessette), none (Smith)

Taste:
not distinctive (Bessette), slightly acid to mild (Smith)

Microscopic:
spores 7-12 x 3-5 microns, fusoid to elongate-oval, smooth, yellowish, (Bessette), spores 7-10(12) x 3-4(5) microns, obscurely fusoid to elongate-ovoid, smooth, inamyloid, pale yellowish in KOH; basidia 4-spored, 26-34 x 5-8 microns, clavate, yellowish in KOH; pleurocystidia "30-46 X 7-10 microns, subcylindric to narrowly clavate or narrowed to a blunt apex, often with incrusting debris", content colorless to dingy yellow-brown, "typically in bunches and at level of hymenium the cluster surrounded by brown incrusting material, as revived in KOH", when fresh colorless to pale vinaceous brown in KOH, cheilocystidia "similar to pleurocystidia, very numerous and tube dissepiments often with copious brown amorphous pigment"; cap epicutis "a layer of gelatinous interwoven hyphae in the form of an interrupted trichodermium the elements of which become fused to form the squamules", these hyphae 8-12 microns wide, with end-cells somewhat cystidioid and 10-16 microns at widest part; caulocystidia abundant, similar to cheilocystidia; clamp connections absent, (Smith)

Spore Deposit:
brown (Bessette), dark olive brown, very slowly changing to dull cinnamon, (Smith)