Clitocybe praemagna (Murrill) H. E. Bigelow & A. H. Sm. 1969

Melanoleuca praemagna Murrill, sp. nov
Pileus large and fleshy, convex to plane, becoming deeply fissured with age or on drying* gregarious, reaching 12-20 cm. broad; surface dry, smooth, glabrous, white, margin involute and minutely downy when young, becoming expanded and glabrous; context thick, white;
lamellae sinuate-adnexed, often with a decurrent tooth, broad, ventricose, crowded, white, becoming dirty-yellowish or brownish on drying ; spores ellipsoid, smooth, hyaline, purewhite in mass, 6-7 X 3-4 ju ; stipe very short, thick and bulbous, smooth, glabrous, white, reaching 5-6 cm. long and 4-5 cm. thick, the bulb being nearly twice this thickness.
Type collected on the crumbling walls of an old sod-house in Saskatchewan, Canada, September 6, 1913, L. H. Pennington. Also collected on high land under sagebrush, near Gunnison, Colorado, August 24, 1899, E. Bartholomew 2611%.
Distribution: Saskatchewan and Colorado.