Hebeloma crustuliniforme

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by Michael Kuo

In the wide sense, "Hebeloma crustuliniforme" is a mycorrhizal associate of both hardwoods and conifers, recognized by its drab, slimy cap and its radishlike odor and taste. It has gills that are attached to the stem (usually by a "notch") and a brown spore print. The stem does not develop the scales that typify Hebeloma sinapizans, but the apex of the stem is often adorned with little flakes of tissue.

However, this description matches a number of Hebeloma species that have been separated on the basis of fine distinctions in some of the features (for example a mild, rather than radishlike, taste) and on microscopic details. Recent DNA research has shown that a few of these species are probably not genetically valid, and has demonstrated that ecological factors may help us to separate some of the remaining species in the cluster with greater confidence; see the comments below for more information.

Description:

Ecology: Mycorrhizal with hardwoods or conifers; growing gregariously or in loose clusters, sometimes in arcs or fairy rings, in grassy areas at woods' edges or in woods; late summer and fall (winter and spring in California); widely distributed in North America.

Cap: 3-11 cm; convex, becoming broadly convex, broadly bell-shaped, or flat; slimy when fresh; smooth; whitish, dirty buff, or pale tan--often with a somewhat darker central area; the margin inrolled when young.

Gills: Attached to the stem, often by a notch; crowded; pale when young, becoming brownish; sometimes with beads of liquid when young and fresh; with whitish edges.

Stem: 4-13 cm long; .5-1.5 cm thick; more or less equal, but with a slightly swollen base; finely hairy or smooth; with little flakes of tissue near the apex; without a cortina or ring zone; the base sometimes with white rhizomorphs.

Flesh: Whitish; thick.

Taste: Beginners should not taste this mushroom; it is poisonous. However, the taste is radishlike, as is the odor of the crushed flesh--and the odor alone will serve to verify the taste.

Spore Print: Brown.

Microscopic Features: Spores 9-13 x 5.5-7.5 µ; lemon-shaped; smooth or minutely roughened. Cheilocystidia abundant; narrowly clavate; 50-85 x 7-9 µ. Clamp connections present.

REFERENCES: (Bulliard, 1787) Quélet, 1872. (Smith, Smith & Weber, 1979; Arora, 1986; States, 1990; Phillips, 1991/2005; Lincoff, 1992; Hansen & Knudsen, 1992; Evenson, 1997; Barron, 1999; Roody, 2003.) Herb. Kuo 11220402, 11230403.

Among the species separated in the Hebeloma crustuliniforme complex are Hebeloma hiemale (smaller, with a slight radishlike odor); Hebeloma helodes (smaller, under pines and birches); Hebeloma sacchariolens (with a sweet odor); and Hebeloma pusillum (much smaller, under willows, with cystidia that have swollen ends).

A study by D. K. Aanen and others (2000) found that some of these species were not clearly differentiated genetically. Specimens identified as Hebeloma helodes and Hebeloma pusillum, for example, did not necessarily line up with other putatively identical specimens. The researchers were able to define two well supported groups, however--one corresponding to mushrooms that are mycorrhizal with willows and poplars, and another corresponding to mushrooms that are less picky about mycorrhizal partners.

Aanen, D. K. et al. (2000). Phylogenetic relationships in the genus Hebeloma based on ITS1 and 2 sequences, with special emphasis on the Hebeloma crustuliniforme complex. Mycologia 92: 269-281.

Further Online Information:

Hebeloma crustuliniforme at MykoWeb
Hebeloma crustuliniforme images at Fungi of Poland

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Cite this page as:

Kuo, M. (2005, February). Hebeloma crustuliniforme. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/hebeloma_crustuliniforme.html