Pluteus mammillatus (Chamaeota sphaerospora)

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Note from Michael Kuo: Chamaeota sphaerospora has recently been synonymized with Chamaeota mammillatus and transferred to Pluteus by Drew Minnis (2006) on the basis of morphological and DNA evidence.

by Ron Meyers

When I spotted a yellow mushroom with pink gills and a ring growing on a log in the Mingo National Wildlife Refuge, I was not particularly impressed. I just assumed it was another mushroom which I had never seen before, interesting but not spectacular. But I decided it was worthy of a photo anyway.

Later, at the campground which serves as the headquarters for the annual Mingo Foray sponsored by the Missouri Mycological Society, Jay Justice approached me to show me a very rare mushroom. It was Chamaeota sphaerospora, and it was the same mushroom I had found earlier.

This mushroom is so rare I cannot locate a published color photo, and the only description I can find is in Kauffman’s 1918 The Gilled Mushrooms of Michigan and the Great Lakes Region. However, the participants at the Mingo Foray do not consider it quite so rare, as they collect it almost every year.

There is no information available as to the edibility of Chamaeota sphaerospora. I do not recommend experimenting.

Description:

Ecology: Saprobic on the decaying wood of hardwoods; growing alone or in loose clusters; summer and fall; distribution uncertain (recorded from Michigan by Peck in 1906, but more recent reports have come from Mingo baldcypress swamp in southeastern Missouri, in August and September).

Cap: 3-5 cm; conical to broadly bell-shaped, becoming flat; dry; silky with brownish fibers; yellow, fading to whitish with a brownish central bump.

Gills: Free from the stem; close; thin; whitish or cream colored, becoming flesh colored from the spores at maturity; edges whitish fringed.

Stem: 3-8 cm long; up to 1 cm thick; equal or tapering upward; solid; fibrous; slightly lined; whitish; with a thin, white ring.

Flesh: Insubstantial; pale.

Odor and Taste: Not distinctive.

Spore Print: Pink.

Chemical Reactions: KOH negative on cap surface.

Microscopic Features: Spores 5-7 µ; round or nearly so; smooth. Cystidia abundant; variously shaped but usually fusoid-ventricose or nearly clavate; up to 100 µ long and 30 µ wide.

REFERENCES: (Longyear, 1902) Minnis, Sundberg & Methven, 2006. (Saccardo, 1912; Kauffman, 1918; Singer, 1978; Miller & Miller, 2006; Minnis, Sundberg, Methven et al., 2006.) Herb. Kuo 09180401.

Pluteus mamillatus (with one m) is an alternate spelling.

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Cite this page as:

Meyers, R. (2004, December). Pluteus mammillatus (Chamaeota sphaerospora). Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/pluteus_mammillatus.html