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Suillus kaibabensis

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

by Michael Kuo

Suillus kaibabensis is one of several western species very close to Suillus granulatus--and, in fact, it may be merely a pale Suillus granulatus growing under ponderosa pines. Aside from the paler cap and association with ponderosa pine, Suillus kaibabensis is hardly distinct, though its glandular dots tend to become large and elongated, and its cap turns reddish (rather than grayish) when a drop of ammonia is applied.

If you are a "lumper" and you're wondering why Harry Thiers, the author of the species, didn't say to himself, "Hey, look at these minor differences in physical features that happen when Suillus granulatus grows under ponderosa pines," rather than, "Hey, a new species," I can't help you. However, preliminary DNA research in Suillus (Kretzer and collaborators, 1996) does indicate that mushrooms in the genus are pretty picky about their mycorrhizal associations--and "Suillus kaibabensis" is a way cooler name.


Ecology: Mycorrhizal with ponderosa pine; growing scattered or gregariously in monsoon season (late July through early September) in the Four Corners region.

Cap: 3-8 cm; convex becoming broadly convex or flat; sticky when fresh; smooth; buff to pale tan or yellowish; the margin at first inrolled.

Pore Surface: Buff to yellowish or yellow, sometimes becoming reddish-dotted with maturity; not bruising; 1-3 angular pores per mm; tubes to 5 mm deep.

Stem: 2-4 cm long; 1-2 cm thick; more or less equal; dry; yellowish to yellow at the apex, whitish to yellowish below; covered with reddish brown glandular dots that frequently become large and elongated with maturity; without a ring.

Flesh: Whitish to yellowish in the cap; yellow in the stem; not staining on exposure.

Odor and Taste: Not distinctive.

Chemical Reactions: Ammonia red on cap surface; pinkish to purplish on flesh. KOH dark gray on cap surface; purplish gray on flesh. Iron salts negative on cap surface; greenish to gray on flesh.

Spore Print: Brown.

Microscopic Features: Spores 7.5-9.5 x 3-4.5 µ; smooth; subfusoid.

REFERENCES: Thiers, 1976. (Thiers, 1976; Thiers, 1979; Both, 1993; Bessette, Roody & Bessette, 2000.) Herb. Kuo 07280601, 08160704.

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


Suillus kaibabensis

Suillus kaibabensis

Suillus kaibabensis

Suillus kaibabensis

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Kuo, M. (2007, December). Suillus kaibabensis. Retrieved from the MushroomExpert.Com Web site: