Agaricus inapertus, commonly known as the mountain gasteroid agaricus,[1] is a species of secotioid fungus in the genus Agaricus. It was first described by American mycologists Rolf Singer and Alexander H. Smith in 1958 as Endoptychum depressum. Molecular analysis later proved it to be aligned with Agaricus, and it was formally transferred in a 2003 publication.