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Suillus granulatus

[ Basidiomycetes > Boletales > Suillaceae > Suillus . . . ]

by Michael Kuo

Regular visitors to this site will recall my disdain for species of Suillus--but I must admit that many of the mushrooms are at least interesting and attractive. Suillus granulatus does not even rise to this level. Brownish and boring, this species has little to brag about. Its distinguishing features include the glandular dots on the stem, the absence of a ring or partial veil remnants on the cap, the white-then-yellow flesh, the patchwork pattern often visible on areas of the mature cap surface, and the pores, which are fairly small and not strongly boletinoid.

Suillus lactifluus is a synonym; the name was formerly applied to a form of Suillus granulatus with a stem that is more yellow in youth, glandular dots that do not darken as much, and a young pore surface frequently beaded with milky droplets; see the illustration to the right.


Ecology: Mycorrhizal with various pines; often appearing in plantations of eastern white pine; growing alone or gregariously; summer and fall--often among the first species of Suillus to appear; widely distributed. In my area (central Illinois) it has quite a long fruiting period, beginning in August or September and lasting through November.

Cap: 5-15 cm; convex becoming broadly convex; sticky or slimy; smooth; variable in color but typically buff, yellowish, or pale cinnamon at first, becoming darker cinnamon brown or orangish brown; often with the color breaking up in maturity to form a patchwork pattern; without partial veil remnants.

Pore Surface: Whitish at first; soon yellowish; often with droplets of cloudy liquid when young; not bruising, or bruising and spotting cinnamon to brownish; pores about 1 mm wide at maturity; not strongly boletinoid but sometimes weakly so in age; tubes about 1 cm deep.

Stem: 4-8 cm long; 1-2 cm thick; equal or with a tapering base; with tiny, tan or brownish glandular dots on the upper half; without a ring; white, developing bright yellow shades near the apex or overall.

Flesh: White at first, but soon pale yellow; not staining on exposure.

Odor and Taste: Not distinctive.

Chemical Reactions: Ammonia is pale gray or bluish gray on the cap surface, pale gray to bluish gray on the flesh, and dull salmon to rusty orange on the pore surface. KOH is olive to bluish gray on the cap surface, grayish or pinkish on the flesh, and dull salmon to rusty orange on the pore surface. Iron salts are olive to grayish on the cap surface, pale green to olive on the flesh, and olive on the pore surface.

Spore Print: Cinnamon brown to brown.

Microscopic Features: Spores 7-9 x 2.5-3.5 µ; smooth; subfusoid.

REFERENCES: (Linnaeus, 1753) Roussel, 1796. (Fries, 1821; Coker & Beers, 1943; Singer, 1945; Smith & Thiers, 1964; Snell & Dick, 1970; Smith & Thiers, 1971; Thiers, 1975; Grund & Harrison, 1976; Smith, Smith & Weber, 1981; Arora, 1986; States, 1990; Phillips, 1991/2005; Lincoff, 1992; Both, 1993; Horn, Kay & Abel, 1993; Evenson, 1997; Barron, 1999; Bessette, Roody & Bessette, 2000; Roody, 2003; McNeil, 2006; Miller & Miller, 2006; Kuo, 2007.) Herb. Kuo 12069402, 09199609, 09190304, 07270403.

This site contains no information about the edibility or toxicity of mushrooms.


Suillus granulatus

Suillus granulatus

Suillus granulatus

Suillus granulatus

Suillus granulatus

Suillus granulatus

Suillus granulatus

Suillus lactifluus
"Suillus lactifluus"
(see comments to the left)

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Cite this page as:

Kuo, M. (2004, November). Suillus granulatus. Retrieved from the MushroomExpert.Com Web site: