Psathyrella piluliformis is a species of agaric fungus in the family Psathyrellaceae. It produces fruit bodies (mushrooms) with broadly convex caps measuring 2–5 cm (0.8–2.0 inches) in diameter. The caps are chestnut to reddish brown, the color fading in age and with dry weather. The closely spaced Gills have an adnate attachment to the stipe. They are initially tan until the spores mature, when the gills turn dark brown. Fragments of the partial veil may remain on the cap margin, and as a wispy band of hairs on the stipe. Fruiting occurs in clusters at the base of hardwood stumps.