Leucoagaricus rubrotinctoides  Murrill (1912)

According to the specialists in the Genus Lepiota there seem to be several hidden species in the rubrotinctoides complex. According to Index Fungorum this taxon still hasn't been formally transferred to Leucoagaricus and remains as Lepiota rubrotinctoides. Until we have more clarity on the matter, I assume that we do not see the original Leucoagaricus rubrotinctus in the Western USA.

Spores: (5.5)6-8 (8.7) x 3.2-4  μ, dextrinoid