Revue Mycol., Paris 5: 9. 1940.
Common Name: none
Solitary to gregarious under conifers in northern North America and Europe. In California it is known from Humboldt, Del Norte, and Mendocino counties.
Edible, but rather tough. Miller & Miller (2006) say it is good pickled.
The very large size, brown cap, and tough flesh make Catathelasma imperiale distinctive. It could be confused with Neolentinus ponderosus, which is another large, white-spored mushroom, but it lacks a veil and grows on wood. It could be also confused with its close relative, Catathelasma ventricosum, which is slightly smaller, with a white to grey cap.
This species has also been (mis)spelled as Catathelasma imperialis.
Bas, C., Kyper, T.W., Noordeloos, M.E. & Vellinga, E.C. (1995). Flora Agaricina Neerlandica -- Critical monographs on the families of agarics and boleti occuring in the Netherlands. Volume 3. Tricholomataceae. A. A. Balkema: Rotterdam, Netherlands. 183 p.
Desjardin, D.E., Wood, M.G. & Stevens, F.A. (2015). California Mushrooms: The Comprehensive Identification Guide. Timber Press: Portland, OR. 560 p.
Smith, A.H. (1949). Mushrooms in their Natural Habitats. Sawyer's Inc: Portland, OR. 626 p.