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Marasmius nigrodiscus

[ Basidiomycetes > Agaricales > Marasmiaceae > Marasmius . . . ]

by Michael Kuo

"That's a Marasmius" is probably not what you'll be thinking when you find Marasmius nigrodiscus for the first time. It is uncharacteristically large for the genus, with a cap that can reach a width of 11 centimeters. It is, however, fairly distinctive, with its dark center and lighter marginal area, and it appears in a wide variety of eastern North American ecosystems--from pine plantations to hardwood forests.

Description:

Ecology: Saprobic on litter under hardwoods or conifers; growing alone or, more often, gregariously; summer and fall; apparently limited to eastern North America.

Cap: 3-11 cm; convex becoming planoconvex or nearly flat, usually with a broad central bump or nipple; dry; often becoming somewhat pitted or wrinkled with maturity and developing fine lines along the margin; when young pale brown, becoming creamy white or very pale brownish with a darker brown or reddish brown center; in old age sometimes uniformly pale brownish or dirty cream.

Gills: Broadly to narrowly attached to the stem; close or nearly distant; whitish, sometimes discoloring grayish.

Stem: 4.5-15 cm long; about 1 cm thick; tough; equal; dry; straight; whitish or very pale brownish; bald or finely silky; smooth or with shallow longitudinal grooves; basal mycelium white.

Flesh: Whitish; thin.

Odor and Taste: Tatse mild or slightly bitter; odor not distinctive or faintly of almonds.

Chemical Reactions: KOH negative to grayish or brownish on cap surface.

Spore Print: White.

Microscopic Features: Spores 7-9 x 3-5 µ; smooth; more or less elliptical; inamyloid. Pleurocystidia abundant; fusoid-ventricose; to 120 x 18 µ. Cheilocystidia cylindric, fusiform, or clavate; to 65 x 15 µ. Pileipellis hymeniform. Trama dextrinoid. Caulocystidia filamentous with subclavate to cylindric apices; to about 75 x 10 µ.

REFERENCES: (Peck, 1897) Halling, 1983. (Saccardo, 1899; Halling, 1983; Weber & Smith, 1985; Roody, 2003.) Herb. Kuo 07010302, 07230407, 08030402, 08310504, 06210801, 06230901.

 

Marasmius nigrodiscus

Marasmius nigrodiscus

Marasmius nigrodiscus
Spore print

Marasmius nigrodiscus
Spores

Marasmius nigrodiscus
Cheilocystidia

Marasmius nigrodiscus
Pleurocystidia

Marasmius nigrodiscus
Caulocystidium



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Cite this page as:

Kuo, M. (2012, July). Marasmius nigrodiscus. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/marasmius_nigrodiscus.html