Hygrocybe pratensis var. pallida

[ Basidiomycetes > Agaricales > Tricholomataceae > Hygrocybe . . . ]

by Michael Kuo

This mushroom is a white variety of Hygrocybe pratensis; aside from its color, it shares the features that define the typical variety: a dry cap with tiny pressed-down fibers, fairly distant gills that run down the stem, stocky stature (for a waxy cap), and microscopic features (see below).

The presence of Hygrocybe pratensis var. pallida in North America has been debated over the years, with some mycologists claiming that other mycologists' collections merely represented old and faded specimens of the typical orangish buff variety. Add to this mess the fact that Hygrocybe virginea and other (putative) species are very similar, and you have a big mess on your hands. Perhaps I am only making the mess worse, but I am treating the illustrated collections, from northern Michigan, as Hygrocybe pratensis var. pallida in order to draw attention to possible variability in the features that currently define the mushroom (see the discussion below if you are interested).

Since the mushrooms described on this page are not even definitively identified, edibility is obviously not something to consider.

Description:

Ecology: Saprobic; found in open areas and grassy places; late summer and fall; North American distribution uncertain.

Cap: 2-10 cm; convex when young, becoming broadly convex, broadly bell-shaped, or flat--or with a shallow central depression and an uplifted margin; dry; with minute, pressed-down fibers (use a hand lens), at least when young; white to off-white (ivory or buff), discoloring yellowish.

Gills: Running down the stem; distant; thick and waxy; whitish, developing yellowish hues.

Stem: 3-10 cm long; up to 2 cm thick; narrowed toward the base; very finely hairy; colored like the cap.

Flesh: White; unchanging when sliced; thick in the cap.

Odor and Taste: Not distinctive.

Spore Print: White.

Microscopic Features: Spores 5-7 x 3.5-5 µ; smooth; broadly elliptical or nearly round. Gill tissue interwoven, with elements 6-10 µ wide. Pileipellis a cutis.

REFERENCES: (Cooke, 1874) Arnolds, 1985. (Boertmann, 2000.) Herb. Kuo 09130406, 09120504.

The description above is based on Boertmann's description (2000) of Hygrocybe pratensis var. pallida in northern Europe. While Boertmann does not mention yellowish discoloration of the cap and gills in his description, his photo clearly depicts a yellowing species (or perhaps Boertmann sees more yellow in the color "ivory" than I do).

My collections come from northern Michigan (Emmet County), and were made in the same location, in September, in consecutive years. The 2004 collection (top illustration) had a dry cap, spores measuring 6-10 X 4-6 µ, and a pileipellis disposed as a non-gelatinized cutis. The 2005 collection (bottom illustration) had a cap that was dry to the touch but featured, under the microscope, a gelatinized cutis; its spores measured 4-7 X 3-4 µ. The 2004 collection matches Hygrocybe pratensis var. pallida in its dry cap, but its spores are too large and too narrowly elliptical. The 2005 collection has spores about the right size (though possibly too narrow) but has a pileipellis indicating a lubricous or greasy fresh cap.

Obviously it is possible that I collected different species in the same location in consecutive years. But another possibility is that spore size and the extent of pileipellis gelatinization are variable--in which case the lines separating Hygrocybe pratensis var. pallida from Hygrocybe virginea begin to become fuzzy. Boertmann places the species epithet berkeleyi in synonymy with the dry-capped Hygrocybe pratensis var. pallida, but the description of this taxon (as Hygrophorus berkeleyi) in Hesler & Smith (1963) calls for a "lubricous to slightly viscid" cap composed of "gelatinous hyphae" and clearly describes a yellowing mushroom, indicating that their concept of Hygrophorus berkeleyi, which they applied to a sole Michigan collection (made about 20 miles from my collection location), differs from Boertmann's. To complicate matters even further, Hesler & Smith's concept of Hygrophorus borealis is also very close; see the discussion on the page for Hygrocybe virginea.

Only a rigorous study of many collections, supported by DNA evidence, can sort out this mess.

Further Online Information:

Hygrophorus berkeleyi in Hesler & Smith (1963)

© MushroomExpert.Com

Cite this page as:

Kuo, M. (2007, January). Hygrocybe pratensis var. pallida. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/hygrocybe_pratensis_pallida.html