Xerula incognita

[ Basidiomycetes > Agaricales > Marasmiaceae > Xerula . . . ]

by Michael Kuo

Xerula incognita is an eastern North American "biological species" supported by mating studies (Petersen & Methven, 1994). It is very similar in appearance to Xerula furfuracea, Xerula megalospora, and to the European species Xerula radicata--but it can be separated from these look-alikes with microscopic analysis (see the Key to 8 Xerula taxa and the information below for details).

Although Xerula incognita has been documented from a relatively small geographic area (from Missouri to North Carolina), it may be more widely distributed, disguised in the records as other, similar species.

Description:

Ecology: Saprobic on decaying debris of hardwoods--but not typically growing on logs or stumps, unless they are well decomposed; usually terrestrial; spring through fall; originally described from Coles County, Illinois, and since documented in Missouri, North Carolina, and Tennessee--perhaps to be expected throughout eastern North America.

Cap: 6-7 cm; convex or broadly conical when young, becoming broadly convex or flat in age, but retaining a broad central bump; fairly smooth, or wrinkled in a zone around the center; greasy in normal weather conditions; brown to yellow-brown before fading.

Gills: Attached to the stem or notched; distant or nearly so; whitish; thick. Gills of dried specimens become yellowish to very pale orangish after several years in storage (compare to Xerula megalospora).

Stem: 6-12 cm long above ground; under 1 cm thick; tapering to apex; fairly smooth; whitish to pale orangish; with a long, tapered tap root extending underground.

Flesh: Whitish, thin.

Odor and Taste: Not distinctive.

Chemical Reactions: KOH on cap surface negative.

Spore Print: White.

Microscopic Features: Spores 13.5-18.5 x 8.5-12 µ; smooth; inamyloid; egg-shaped or slightly lemon-shaped to flask-shaped. Cheilocystidia broadly fusoid; up to 80 x 25 µ. Pleurocystidia fat-cylindric to broadly subclavate; to 95 x 35 µ. Pileipellis hymeniform and somewhat gelatinized; pileocystidia scattered, thin-walled, hyaline, up to 115 x 8 µ. Caulocystidia narrowly fusoid.

REFERENCES: Methven & Petersen, 1994. (Methven & Petersen, 1994.) Herb. Kuo 06170202, 05120705, 05170705, 05170706, 05240802.

Spores

Cheilocystidia

Pleurocystidia

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Cite this page as:

Kuo, M. (2008, October). Xerula incognita. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/xerula_incognita.html