Suillus subaureus
Description
Suillus subaureus is a rare species of bolete fungus in the family Suillaceae. It is found in North America, where it associates with deciduous trees. Fruit bodies are pale yellow—reflecting its specific epithet subaureus, which means "somewhat golden yellow". The spore print is olive-brown. Spores are smooth and inamyloid, and measure 7–10 by 2.7–3.5 µm. It has also been recorded in Taiwan.
A recent study of this species indicates that S. subaureus associates with both deciduous and conifer trees in eastern North American forests. The spores of S. subaureus will not germinate in the presence of only deciduous tree roots. Instead, they require the presence of a conifer host tree (preferably Pinus) to germinate, but will then colonize and persist on deciduous hosts via mycelial extension.
Suillus subaureus originally described in 1887 by Charles Horton Peck, it was transferred to genus Suillus by Wally Snell in 1944.
Mushroom Identification
Ecology
Mycorrhizal with quaking aspen and big-toothed aspen, as well as eastern white pine; occasionally reported under scrub oak; growing alone, scattered, or gregariously; summer and fall; northeastern North America.
Cap
3-17 cm; convex becoming broadly convex or flat; slimy and yellow underneath scattered brownish to reddish, appressed fibers and down; often developing a reddish-spotted or streaked appearance; when young with a cottony to felty roll of marginal tissue that sometimes persists into maturity as an inrolled sterile margin. The cap stains waxed paper bright yellow.
Pore Surface
Pale orange to orange or yellowish; not bruising; pores angular and radially arranged, about 2 per mm across; tubes to 1 cm deep.
Stem
4-8 cm long; 1-2 cm thick; more or less equal; sticky when young; yellowish, discoloring brownish on handling; by maturity with visible brownish glandular dots; without a ring.
Flesh
Yellow; not staining on exposure, or staining pinkish to reddish.
Odor and Taste
Not distinctive.
Chemical Reactions
Ammonia on cap surface olive to red or pinkish; on flesh reddish to pinkish. KOH negative to bluish on cap surface; pinkish, grayish, or purplish on flesh. Iron salts negative on cap surface; olive to negative on flesh.
Spore Print
Olive brown.
Microscopic Features
Spores 7-10 x 3-4 µ; smooth; subfusoid.
Photo sources:
Photo 1 - Author: Jimmie Veitch (jimmiev) (CC BY-SA 3.0)
Photo 2 - Author: walt sturgeon (Mycowalt) (CC BY-SA 3.0)
Photo 3 - Author: Jason Hollinger (CC BY-SA 2.0)
Photo 4 - Author: Jason Hollinger (CC BY-SA 2.0)
