Originally described from Texas but today found in ten states of North America, the mushroom grows in lawns, pastures and prairies.

It is a saprotroph, living on decaying plant material, and not mycorrhizal as is the case with species of Amanita, where it was previously placed.

Sapromanita thiersii was first described in 1957 by American mycologist Harry Delbert Thiers, who had spotted it on a campus lawn when he was a student.

[1][6][7] The cap is white and dry, measuring 3.5–10 centimetres (1+1⁄2–4 inches) wide, and convex in shape (conico- or plano-convex).

All the spores were found to be binucleate but the researchers believed that in the monokaryotic strain, the second nucleus had failed to pass through the germ tube.

[4] S. thiersii may be gathered inadvertently and thought to be edible due to the fact that it grows on lawns among grasses.

[9][13] A. silvifuga is another species that grows in similar locations in grassland in Texas and H. D. Thiers described the taste of both it and A. thiersii as being bitter.

[8] Analysis using stable carbon isotopes has proved that this mushroom is saprotrophic in nature, unlike the other mycorrhizal Amanitas.

[17] Today it occurs in nine states including Missouri, Oklahoma, Texas, Kentucky, Ohio, Kansas, Iowa, Indiana, Illinois.

[4] The main source from which S. thiersii derives its carbon is the cellulose of the decomposing plant material found in its grassland habitat.

In an attempt to identify the genes involved in these processes, researchers at the United States Department of Energy and University of Wisconsin are jointly working to sequence the S. thiersii genome and to compare it with that of Amanita bisporigera, a species which forms mycorrhizal relationships with tree[18] and which has already been partly sequenced.

Another research objective is to establish whether the enzymes used by S. thiersii to degrade cellulose can be cost-effectively used in the conversion of crop residues into biofuels.

S. thiersii seems to be expanding its range northwards and its genome may provide clues as to how it is adapting to climate change and further information on mycorrhizal relationships.

DNA analysis has shown that a group of species in the subsection Vittadiniae (which includes S. thiersii) has few derived characteristics.