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Suillus luteus: The Slippery Jack

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

by Michael Kuo

Whether 'tis nobler in the mind to suffer
The slimes and swallows of outrageous fungi,
Or to take arms against a sea of Suillus,
And, by opposing, end them.

Yes, that is the question. You can pick the "Slippery Jack" (only one of those word is operative!)--or you can kick it, and all its slimy little friends, beat them all to a gooey pulp with your walking stick, smash them against trees, scream bloody murder at the top of your lungs . . .

Excuse me. I was trying to say that Suillus luteus is an impressive and beautiful fall mushroom, easily recognized by its stature, its glutinous brown cap, and its distinctive ring, which is white at first but soon develops purple shades.

Smith and Thiers (1964) record a form of this mushroom with no ring, under introduced Scots pine, in Michigan.


Ecology: Mycorrhizal with various conifers; growing gregariously; late summer and fall--or in winter during warm spells; widely distributed in North America. In my area (central Illinois) Suillus luteus grows in both red pine and eastern white pine plantations. Curiously, in plantations where rows of both trees occur, it always seems to stick with one or the other species.

Cap: 5-12 cm; convex when young, becoming broadly convex to flat; slimy; shiny when dry; partial veil tissue often hanging from the margin; dark brown to dark reddish brown to yellow brown; fading with age.

Pore Surface: Covered with a whitish partial veil when young; whitish to pale yellow, becoming yellow to olive yellow with age; not bruising; pores under 1 mm across; tubes 4-15 mm deep.

Stem: 3-8 cm long; 1-2.5 cm thick; equal; with glandular dots above the ring; whitish, yellowish towards apex; discoloring brown to purplish brown near the base in age; with a flaring white ring that develops purple shades on the underside and is often gelatinous in humid or wet weather.

Flesh: White to pale yellow; not staining on exposure.

Odor and Taste: Not distinctive.

Chemical Reactions: Cap surface gray with KOH or ammonia, grayish olive with iron salts; flesh bluish to olive with iron salts, pinkish, then pale bluish with KOH or ammonia; pore surface rusty red with ammonia, brownish with KOH or iron salts.

Spore Print: Brown.

Microscopic Features: Spores 7-9 x 2.5-3 µ; smooth; subfusoid.

REFERENCES: Linneus, 1753. (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; Phillips, 1991/2005; Lincoff, 1992; Both, 1993; Barron, 1999; Bessette, Roody & Bessette, 2000; Roody, 2003; McNeil, 2006; Miller & Miller, 2006; Kuo, 2007.) Herb. Kuo 11149402, 09299602, 10310405, 11120402.

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


Suillus luteus

Suillus luteus

Suillus luteus

Suillus luteus

Suillus luteus

Suillus luteus

Suillus luteus

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Kuo, M. (2004, November). Suillus luteus: The slippery jack. Retrieved from the MushroomExpert.Com Web site: