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Species Information
Summary: There is not yet clear evidence that either European Suillus granulatus or eastern North American Suillus ''granulatus'' (which needs a new name) occurs in the Pacific Northwest, although identifications have been made (see Range). Features of North American Suillus ''granulatus'' include 1) viscid to glutinous cap that is whitish, tan, brown, cinnamon, or orange-cinnamon, 2) whitish to yellowish pores that stain dull cinnamon, 3) whitish to pale yellow flesh that does not turn blue, 4) whitish to yellowish stem with conspicuous pinkish tan to brown dots, 5) absent veil, and 6) growth under pine. North American Suillus ''granulatus'' (which associates with soft pines) is not genetically close to European Suillus granulatus (which associates with hard pines) in the work of Nguyen(3). The latter paper proposed in 2006 the use of the name Suillus weaverae for North American Suillus ''granulatus''. However the situation does not appear completely resolved because 1) the Suillus weaverae clade is nested within the Suillus placidus/subalpinus/anomalus complex in Nguyen(3), and 2) The online Species Fungorum, accessed February 24, 2018, gives the current name of Suillus weaverae as Fuscoboletus weaverae. The three other Fuscoboletinus species in the online Species Fungorum, F. spectabilis, F. glandulosus, and F. grisellus, are located in two other parts of the Nguyen(3) tree - note that MycoBank (accessed the same day) gives the Suillus names of these three as obligate synonyms and does not designate a current name. Incidentally, both the online Index Fungorum and MycoBank on that day gave two competing 1996 authorities for Suillus weaverae. Cloudy droplets often cling to the pores of Suillus ''granulatus'', giving it the name "milk bolete", (Schalkwijk-Barendsen).
S. ''granulatus'' is found in eastern Canada south to SC, west to CA and the Pacific Northwest, (Bessette). It was collected from ID (Smith(36) who discuss the similarity to Suillus punctatipes about which they comment "It is, to all practical purposes, a S. granulatus with a boletinoid configuration of the tube mouths." [Latin name italicized]). For the Smith(36) study they studied 3 collections of S. punctatipes and 10 collections of S. granulatus. It has also been recorded from WA and OR, (vouchered at University of Washington), MI (Smith(35)), NS, and NC, (Lincoff(2)). It has been reported from BC (in Redhead).
Cap: 5-12cm, broadly convex; pale yellow or some shade of tan, brown, cinnamon, or orangish cinnamon; viscid to glutinous and often streaked or checkered when fresh; margin even when young and when mature, (Bessette), 5-11(15)cm, becoming broadly convex; bald or streaked or spotted with "cinnamon" (Ridgway color) on a pale buff ground color, when old more or less cinnamon overall, "immature specimens often pallid for a long time", some fully developed caps almost dingy white; viscid to glutinous when wet, tends to become spotted from aggregations of gluten, often minutely areolate [cracked like dried mud] when old; margin bald to minutely tomentose, (Smith(34)), convex to flat or slightly wavy; "cinnamon-brown to brown, orange-brown, rusty-cinnamon, or yellow-brown (but in some forms whitish when young)", (Arora), margin bald, rarely with a minute tomentum on margins of immature caps, (Palm)
Flesh: white to pale yellow, not turning blue when cut or bruised, (Bessette), soft; whitish when young but soon pale yellow, unchanging, "with a watery green line above the tubes"; in stem white at first but soon bright yellow at top, tinged cinnamon toward base, (Smith(34))
Pores: 1 per mm, irregular; whitish to pinkish buff when young, soon yellowish, staining dull cinnamon when old or when bruised, sometimes unchanging; tube layer 0.4-1cm thick, (Bessette), about 2 per mm, or in old caps 1 per mm and somewhat boletinoid [radially arranged] to merely elongated; pale honey yellowish, when old brownish spotted, "staining dingy cinnamon when bruised, in very young stages beaded with droplets of a cloudy liquid"; tube layer about 1cm thick, adnate-subdecurrent, "pallid at first, but soon pale yellow becoming dingy yellow, not staining when bruised", (Smith(34)), whitish when very young, "soon becoming buff or yellow and eventually dingy yellowish or brownish-spotted when mature", (Arora)
Stem: 4-8cm x 1-2.5cm, nearly equal, solid; whitish when young, becoming yellowish when old especially at top; "with conspicuous pinkish tan to brownish glandular dots and smears; partial veil and annulus absent", (Bessette), 4-8cm x 1-2(2.5)cm at top, "equal or narrowed to a point at base, solid"; whitish but soon bright yellow in upper part, "pallid downward but base becoming dingy cinnamon"; "covered over all by pinkish tan to vinaceous brown glandular dots; veil none", (Smith(34) who also comment that stem is white at first with vinaceous spots and smears over the apex and it gradually becomes yellow, nearly lemon yellow at times, and some specimens change to this color slowly after handling), (Smith(34)), whitish when young, becoming yellow in upper part and dingy cinnamon-stained or reddish stained toward base; "covered with pinkish to reddish-tan or brown glandular dots and smears in age", (Arora), dots on stem exude milky droplets (Phillips)
Chemical Reactions: cap cuticle stains dark olive to olive-gray with application of KOH and bluish gray with FeSO4, flesh stains pink then pinkish brown with KOH and olive gray with application of FeSO4; stem surface purplish brown with application of KOH and dark green with FeSO4; pore surface instantly rusty orange then rapidly purplish brown with application of KOH, olive green with FeSO4, (Bessette)
Odor: not distinctive (Bessette), mild to slightly fragrant (Smith(34)), pleasant, slightly acid, fruity, (Lincoff(1))
Taste: not distinctive (Bessette), mild to acid (cap cuticle) (Smith(34))
Microscopic: spores 7-10 x 2.5-3.5 microns, oblong or tapered slightly to apex, pale brown, (Bessette), spores 7-9(10) x 2.5-3.5 microns, oblong or tapered slightly to the apex, smooth, yellowish in Melzer''s reagent and KOH; basidia 4-spored, 18-24 x 5-6 microns, clavate, colorless in KOH; pleurocystidia "in bundles with brown incrusted material around base", individually 36-50 x 7-9 microns, clavate to subcylindric, colorless or with yellowish to brown content, cheilocystidia similar; cap epicutis a gelatinous trichodermium of hyphae 4-7 microns wide, "in KOH the content dingy ochraceous to bister, some encrusting material present in the layer"; caulocystidia "40-70 x 7-10 microns, clavate, subfusoid or cylindric, mostly with colored content, bases of clusters surrounded by brown pigment", content of cystidia colorless to colored and mostly coagulated, "incrusting pigment present over much of caulohymenium"; clamp connections absent, (Smith(34))
Spore Deposit: brown (Bessette), dingy cinnamon to cinnamon (Smith(34)), brown to dull cinnamon or ocher (Arora), dingy cinnamon to red-brown (Miller)
Habitat / Range
scattered or in groups on the ground under pines, (Bessette), scattered to gregarious under pine (Smith(34)), especially under 5-needle white pines; late spring, summer, and fall, (Miller), spring, summer, fall, winter
Similar Species
Suillus brevipes has a glutinous reddish brown cap and short stem that lacks glandular dots or has sparse glandular dots when old, (Bessette). Suillus punctatipes is larger and thicker-stemmed with larger pores and a somewhat different RANGE of cap color (orange-brown to dark brown, dingy tan, pinkish brown, gray, vinaceous gray, or purple-tinged), (Arora). Suillus neoalbidipes has a distinct band of cottony tissue on the margin of young caps, small clusters of caulocystidia, and rare to few clusters of pleurocystidia, whereas S. granulatus has a bald cap margin rarely with a minute tomentum on the immature cap margin, large clusters of caulocystidia, and numerous clusters of pleurocystidia, (Palm). Suillus glandulosipes has a conspicuous cottony roll on the margin when young, (Bessette).
edible, but note that a few people develop contact dermatitis with swelling and itchy rash on handling this species, (Bessette), occasionally gastric upset has resulted (Miller)
