Per Bas (1969), Amanita stirps Cinereoconia comprises all and only those species satisfying the following conditions: (1) clamps are absent from the basidia; (2) the spore length range is 7.5 - 12.5 μm; (3) the universal veil is a shade of gray or brown; (4) microscopically, the universal veil consists of abundant small to medium-sized inflated cells and scarce to abundant filamentous hyphase, with these elements organized vertically or disordered; (5) macroscopically, this results in the universal veil on the pileus being pulverulent to pulverulent-floccose and forming a continuous layer or forming patches or small warts.
Bas notes that this group includes "the small to medium [clampless] species of subsection Solitariae with more or less pulverulent, greyish or brownish volva and usually ellipsoid to cylindrical spores."