Major Groups > Mycotrophs > Clitocybe sclerotoidea
Major Groups > Gilled Mushrooms > Pale-Spored > Clitocyboid Mushrooms > Clitocybe sclerotoidea


Clitocybe sclerotoidea

[Basidiomycetes > Agaricales > Tricholomataceae > Clitocybe...]

by Michael Kuo

Poor Helvella lacunosa. Despite being one of the coolest, funkiest mushrooms around, it just can't seem to catch a break. It is regularly parasitized by both Hypomyces cervinigenus and Clitocybe sclerotoidea.

A gilled mushroom like Clitocybe sclerotoidea parasitizing an ascomycete is a bit of a novelty; usually it is the other way around--or the gilled mushroom parasitizes another gilled mushroom, as in the case of Entoloma abortivum, which attacks Armillaria mellea (though scientists used to think the parasitism was reversed). But Clitocybe sclerotoidea does, indeed, appear to "require Helvella-produced metabolites for initiation or maturation" of mushrooms (Trappe, 1972). Microscopic analysis of the large, swollen mass that is always at the base of Clitocybe sclerotoidea reveals the presence of cells from both species, and proves the direction of the parasitism.

Clitocybe sclerotoidea is thus easily recognized by the fact that it grows with Helvella lacunosa in the Pacific Northwest and has a stem that arises from a swollen mass of tissue. Its dirty whitish cap, darkening gills, lack of a distinctive odor or taste, and microscopic features also help to distinguish it. The surest way to identify the species, however, is to ask the kind and delightful James Trappe (who discovered the parasitic relationship with Helvella lacunosa) to pop some out of his car so that you can take a picture for your Web site, as in the bottom illustration.


Ecology: Parasitic on Helvella lacunosa; growing under conifers in clusters, often with malformed mushrooms also present; fall and winter (rarely in summer); Pacific Northwest. Arora (1986) notes that Clitocybe sclerotoidea appears only to parasitize Helvella lacunosa when it grows under conifers, raising the possibility that there are further, as yet unstudied, dimensions to the ecology of this species.

Cap: 1-5 cm; convex, becoming flat or very shallowly vase-shaped; smooth to the naked eye but densely hairy with a hand lens; dirty whitish to pale grayish or brownish, often with watery spots; the margin at first inrolled.

Gills: Attached to the stem or beginning to run down it; nearly distant; whitish at first, darkening to grayish brown.

Stem: 2-6 cm long; up to 1.5 cm thick; more or less equal; finely velvety or hairy; arising from a swollen mass of fuzzy white tissue measuring up to 6 x 4 cm.

Flesh: Whitish.

Odor and Taste: Not distinctive.

Spore Print: White.

Chemical Reactions: KOH on cap surface negative.

Microscopic Details: Spores 8-11 x 3-4 µ; nearly spindle-shaped; smooth; inamyloid. Clamp connections present. Cuticle with somewhat gelatinized hyphae in a KOH mount.

REFERENCES: Bigelow, 1958. (Trappe, 1972; Smith, 1975; Smith, Smith & Weber, 1979; Bigelow, 1982; Arora, 1986.) Herb. Kuo 01150501.

This site contains no information about the edibility or toxicity of mushrooms.


Clitocybe sclerotoidea

Clitocybe sclerotoidea

© MushroomExpert.Com

Cite this page as:

Kuo, M. (2005, January). Clitocybe sclerotoidea. Retrieved from the MushroomExpert.Com Web site: