Inocybe tahquamenonensis is an inedible species of agaric fungus in the family Inocybaceae.

[1] Found in the United States, it was formally described in 1954 by mycologist Daniel E.

[2] The fruit bodies have bell-shaped to convex to flattened caps measuring 1.2–3 cm (0.5–1.2 in) in diameter.

Its color is dark purplish brown to reddish- or blackish-brown, with reddish-purple flesh.

Fruit bodies grow singly, scattered, or in group under deciduous trees.