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

Summary:
Features include 1) a cap with olive-brown to dark brown fibrils or fibrillose scales, 2) whitish to yellowish flesh that does not turn blue, 3) yellowish pores that do not change color, 4) whitish to yellowish stem with conspicuous dots that are colored like the stem then brown, and 5) growth under pine.

Suillus fuscotomentosus is found in OR and CA (Bessette). Oregon State University has one collection from OR labeled as this species, and the University of British Columbia has one collection from BC labeled as this species.

Cap:
4-15cm, convex to flat; "at first covered with olive-brown to dark brown or fuscous [deep grayish brown] fibrils or small fibrillose scales", the scales often sparser when old revealing the paler (dull ocher to buff) ground color, sometimes more cinnamon overall when mature or appearing streaked; dry, or viscid when old or in wet weather; margin bald, (Arora), 3.5-15cm, subconic to convex to obtusely convex, becoming broadly convex to flat-convex, occasionally very irregular with wavy margin; when young colored olive brown near to fuscous on the disc, unchanging or fading slightly toward the margin, when old slowly fading to dark vinaceous brown, eventually becoming near cinnamon, fibrils more or less the same color as the surface or darker than the surface; moist to obscurely viscid when old, conspicuously fibrillose to fibrillose-scaly to almost squamulose when young, fibrils often becoming agglutinated at tips, sometimes becoming less dense when old and appearing appressed, sometimes appearing bald when very old; margin without veil remnants (no evidence of partial veil at any stage), (Smith), "when young densely covered with olive-brown to dark brown or vinaceous brown fibrils, mature specimens with a thinner and more widely separated layer of brown fibrils on a buff to yellow or pale ochre ground color", (Bessette)

Flesh:
thick; "yellow to pale orange or orange-buff", not turning blue when bruised, (Arora), 1-2cm thick at disc, whitish, changing to yellowish when older, unchanging when exposed; in stem colored as stem surface and unchanging when exposed, (Smith), pale yellow to yellow (Bessette)

Pores:
"typically orange-buff when young and sometimes beaded with droplets, becoming yellowish-buff to dark dingy yellow or olive-yellow" when old, not turning blue when bruised; tubes the same color, (Arora), up to 1mm, often less and rarely more, angular; pale yellow when young, finally becoming olive yellow, unchanging when bruised, tube layer up to 1.5cm thick, adnate to shallowly and narrowly depressed around stem, unchanging or becoming subdecurrent to broadly shallowly depressed when old, colored as pores and unchanging when bruised or exposed, (Smith), 1-2 per mm, angular; "pale yellow at first, becoming yellow to olive-yellow or dull golden yellow" when mature, not staining when bruised; tube layer 0.8-1.5cm thick, (Bessette)

Stem:
4-12cm x 1-3cm, equal or somewhat wider in lower part, solid, firm; "pallid to yellow or brownish-buff or often pinkish-orange to pale orange, especially toward base", glandular dots and smears present, usually conspicuous at least when old, often elongated, colored as stem or darker (brown to cinnamon); veil absent, (Arora), 4-10cm x 1-3cm at top, equal to typically obscurely clavate to clavate, solid; '' when young colored near "Naples yellow" to "mustard yellow", with age sometimes becoming near "amber yellow" to "strontian yellow" at the apex, typically becoming "pale olive buff" to "warm buff", occasionally becoming "pale pinkish vinaceous", particularly at the base'' (Ridgway colors), unchanging on bruising; moist but not viscid, strongly punctate, glands relatively large and often becoming elongated when old, colored more or less as the surface but darkening when handled; no annulus; mycelium at base white to "avellaneous" (Ridgway color), (Smith), solid; yellow to pale yellow; dry, with dense conspicuous brown to vinaceous brown glandular dots; partial veil and annulus absent, (Bessette)

Chemical Reactions:
cap cuticle black with application of KOH, negative with FeSO4; flesh gives a pink flash then grayish pink with application of KOH, greenish gray with FeSO4, (Bessette)

Odor:
not distinctive (Smith)

Taste:
not distinctive to weakly acid and unpleasant, (Smith)

Microscopic:
spores 9-12 x 3-4 microns, spindle-shaped to elliptic, smooth, (Arora), spores 9-12 x 3-4 microns, fusoid to subelliptic to subcylindric, smooth, pale ochraceous in Melzer''s reagent, pale yellow in KOH, thin-walled; basidia apparently 2-spored to 4-spored, 21-24 x 6-8 microns, clavate, colorless; cystidia in clusters or fascicles, rare to absent on sides of tubes, but abundant on pores, 30-45 x 8-10 microns, cylindric to subclavate to obtusely fusoid to highly irregular in shape, typically staining dark brown to black in KOH, appearing incrusted near the pores, often only basal part of cluster staining when on sides of tubes; cap cuticle "a highly uneven turf of more or less erect, septate hyphal tips, not at all or only slightly gelatinous in KOH, hyphae typically appearing incrusted, and staining pale brown", cells +/- 7 microns wide; surface of stem "not gelatinous in KOH, with numerous large clusters of caulocystidia" 60-90 x 6-10 microns individually, which stain dark vinaceous to black in KOH, cylindric to highly irregular in shape; clamp connections not seen, (Smith)

Spore Deposit:
olive-brown to dull cinnamon-brown (Arora), olive-brown (Bessette)