Amanita thiersii, commonly called Thiers' lepidella, is a North-American saprotrophic basidiomycete fungus in the genus Amanita. It is a white mushroom originally described from Texas but today found in nine states of North America. It was named after Harry Delbert Thiers. The cap of this small mushroom is white and convex, measuring 35–100 mm (1.4–3.9 in) and covered by volval remnants. It is sticky to the touch when wet. The gills are variable in length and number and are densely packed in some specimens and widely spaced in others. They are not attached to the stipe, which is 8–20 cm (3–8 in) long and about 1 cm (0.4 in) thick, with a white ring. The spores measure 7.8–9.8 by 7.3–9.0 µm and are roughly spherical in shape. The spore print is white.