Tricholoma vernaticum is an agaric fungus of the genus Tricholoma native to the Pacific Northwest region of the United States. The fungus was originally described in 1976 as a species of Armillaria when that genus was more inclusive; it received its current name twenty years later. The stout fruit bodies (mushrooms) have moist white to grayish caps (later becoming grayish-brown with age), a membranous ring on the stipe, and an odor resembling cucumbers. Mycorrhizal with conifers, the fungus fruits in the spring or early summer, with its mushrooms appearing on the ground singly or in groups at high elevations, often at the edge of melting snowbanks. The edibility of the mushroom is unknown, but it has a strong unpleasant odor and a mealy taste.