Tricholoma arvernense, also known as the Deceptive Tricholoma, is a medium-sized mushroom species that belongs to the Tricholoma genus. Often found in association with coniferous trees, particularly in temperate forests, this mushroom is notable for its brown and yellowish cap and whitish gills. Its appearance can vary, making identification somewhat tricky, hence the name "deceptive." Its fruiting season typically spans from late summer to autumn, making it a frequent find in cooler months.

Cap at first convex with a central bump, becoming broadly convex to broadly bell-shaped. It is dry with finely, radially appressed-fibrillose texture, featuring brownish yellow fibrils on a yellowish ground or, near the margin, on a whitish ground. The centre is usually darker and more brown. Gills whitish, attached to the stem by a notch and are close together. Short-gills are frequent. Stem equal or swollen in the middle, bald, and dry. It is whitish in color and develops brownish stains in places. Spore print white.

Microscopic Features: Spores measure 4–6 x 3.5–4.5 µm and are ellipsoid with a small apiculus. They are smooth, hyaline in KOH, and inamyloid.

Tricholoma arvernense on the MushroomExpert.Com Web site.

The second photo is by Irene Andersson under the Attribution-ShareAlike 3.0 Unported license.