The featured mushroom for November 2011 was... Tricholoma myomyces: Mouse’s ears
Tricholoma myomyces, a small grayish brown mushroom, is the most common species in the Tricholoma terreum complex, a group of small grayish brown Tricholomas. Mouse’s ears are associated with conifers and locally are found predominantly with white pines. Though this is a small mushroom, it grows in great profusion. Usually when you find one you will find many. According to David Arora in Mushrooms Demystified, the Tricholoma terreum complex contains the species: T. terreum, T. myomyces, T. squarrulosum, T. orirubens, and T. argyraceum aka T. scalpturatum. T. myomyces can be distinguished by have a cortina (cobweb-like veil); unfortunately this cortina is very evanescent as are the slight remnants it leaves on the stalk. It is rare to find a mouse’s ear that still has a cortina or any remnants thereof.
T. myomyces have a cap that is ½ to 2 ½ inches across with dense grayish brown to blackish scales or fibrils yielding a “furry” appearance that often becomes paler near the margin. The caps start out conical and nearly black with inrolled margins, the stage at which you might see a cortina, but they soon expand to convex or flat with a flattish umbo (outie). The grayish gills are attached sinuate. The slightly tapered stem is ½ to 2 ½ inches tall and ¼ to ½ inches thick and is solid or hollow. The stem is white to very pale gray with white or gray hairs. The flesh is pale gray with a mild flavor. The mouse’s ears fruit relatively late in the mushroom year; we often can pick these on Thanksgiving weekend.
In addition to the other members of the complex, T. myomyces has several other look-alikes: the not edible T. saponaceum whose soapy odor is distinct, the edible, larger T.portentosum with a mealy odor and taste, the poisonous (causes severe gastroenteritis) T. pardinum which is larger and lighter colored with fewer fibers or scales and with those concentrated at the center, and the not edible T. virgatum with a bitter and peppery taste.
Mouse’s ears are edible and are quite prolific so we often find them in great quantities in the late fall. The larger T. portentosum is a better edible but is not as common as the Mouse’s ears. Because of the many look-alikes, one of which causes severe gastrointestinal upset, this mushroom is not highly recommended as an edible by our guide books. Many of us do pick and eat this mushroom taking care not to pick a poisonous T. pardinum with our mouse’s ears primarily because it is available when few other species are fruiting. I found only two references to Tricholomas other than Matsutakes in 24 mushroom cookbooks. A Cook’s Book of Mushrooms and Joe’s Book of Mushroom Cookery both by Jack Czarnecki mention Tricholomas, both T. portentosum and T. myomyces, and the latter book gives a recipe for Tricholoma and Potato Soup.