Helvella macropus species cluster

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by Michael Kuo

A number of Helvella species form a cluster of hard-to-distinguish mushrooms that have cup-shaped or disc-shaped to flat caps and finely hairy, skinny stems that are not ribbed. The true Helvella macropus is easily distinguished with the use of a microscope, however; its spores are spindle-shaped rather than elliptical. Helvella macropus is described below; some information on look-alike species follows.

Helvella macropus is frequently the victim of parasitism on the part of Hypomyces cervinigenus. The top specimen in the third illustration is an example.

Description:

Ecology: Uncertain (potentially saprobic and/or mycorrhizal, like the morels); growing alone or gregariously on the ground under hardwoods or conifers, or on rotting wood; summer to fall (winter in California); widely distributed in North America.

Cap: 1-5 cm; cup-shaped or disc-shaped, occasionally nearly flat; upper surface brownish, smooth; undersurface colored like the upper surface, finely hairy (especially near the margin; use a magnifying glass).

Flesh: Thin.

Stem: 1-5 cm long; to .5 cm thick; more or less even; sometimes with clefts near the base in age; colored like the undersurface of the cap; finely hairy.

Microscopic Features: Spores 21-24 x 10.5-12.5 µ; spindle-shaped; smooth or slightly rough; with one large central oil droplet and another, smaller oil droplet at each end.

REFERENCES: (Fries, 1822) Karsten, 1870. (Smith Weber, 1972; Arora, 1986; Lincoff, 1992; Abbott & Currah, 1997.) Herb. Kuo 07209401, FMP 06170206, 05230302, 06010407.

Helvella macropus var. brevis is nearly identical, but is shorter (stem under 2 cm long), and has shorter spores (18-23 x 10.5-12 µ).

Several species are similar in macrofeatures, but have elliptical rather than spindle-shaped spores. They include Helvella villosa, with a darker cap that seems to fold over more and become flat or even convex; Helvella corium, a small northern species with a jet black cap; Helvella cupuliformis, with a pale underside and stem (illustrated, bottom); and Helvella pallidula, with pale, drab colors.

Further Online Information:

Helvella macropus at Fungi of Poland

Helvella cupuliformis

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Cite this page as:

Kuo, M. (2003, February). Helvella macropus species cluster. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/helvella_macropus.html