Helvella corium

[ Ascomycetes > Pezizales > Helvellaceae > Helvella . . . ]

by Michael Kuo

Helvella corium is recognized by its cup-like to flat, jet black cap and its relatively smooth, blackish stem, which may develop shallow ribs in older specimens. It appears to be primarily a boreal species, appearing primarily north of the Great Lakes. I have never seen it in the fresh state, unfortunately--but I have studied preserved collections from Alaska and northern Michigan.

Thanks to the Herbarium of the University of Michigan for facilitating study of the collections cited below.

Description:

Ecology: Probably mycorrhizal; growing in woods, in sandy soil, or in debris areas, often near willows or aspens; May to August; widely distributed in boreal and montane North America north of roughly the 42nd parallel.

Cap: 1-7 cm across; cup shaped, saucer shaped, or nearly flat; upper surface smooth, or roughened near the center, bald; undersurface black, sometimes whitish at the margin, very finely hairy.

Stem: 1-4 cm long; 2-15 mm thick; black or very dark brown; sometimes grayish near the base; bald or finely hairy; sometimes with shallow ribs when mature.

Microscopic Features: Spores 16.5-21 x 9-15 µ; elliptical; smooth; usually with one large oil droplet. Paraphyses cylindric with clavate apices; brown; 3.5-9 µ wide. Asci 8-spored. Elements on excipular surface in chains; swollen but constricted at septa; terminal cell clavate to subglobose, up to 25 µ across; brown in KOH.

REFERENCES: (Weberbauer, 1873) Massee, 1895. (Saccardo, 1889; Smith Weber, 1972; Smith, Smith & Weber, 1981; Abbot & Currah, 1997; Bunyard, 2012.) Herb. MICH 00001552 (Wells & Kempton 1532), 00053377 (Wells & Kempton 5489), 00021851 (N. J. Smith 1015).

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Spores

Asci and paraphyses

Elements on excipular surface

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Kuo, M. (2012, July). Helvella corium. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/helvella_corium.html