Type species: Agaricus campestris L., Sp. Pl. 2: 1173 : Fr., Syst. Mycol. 1:281. 1821.
Agaricus subgenus Agaricus only contains A. section Agaricus.
Delimitation of Agaricus subgenus Agaricus and A. section Agaricus: The diagnosis of this subgenus is the same as that of A. section Agaricus. KOH and Schäffer’s reactions negative on white areas of the surface of the pileus. Pileus surface unchanging or slightly yellowing, rarely rufescent on touching. Context often turning pink or strongly reddening and then becoming brownish over time near the connection between the stipe and pileus, and sometimes yellow at the base of the stipe on exposure. Odour usually indistinct or mushroomy, but in some species of anise in young basidiomes. Annulus superous or intermediate, simple or double, membranous or fibrillose. Cheilocystidia absent or indistinct, basidia-like, some species abundant, large, globose, piriform or ovoid, such as A. langei (F.H. Møller) F.H. Møller and A. depauperatus (F.H. Møller) Pilát, never catenulate.
– Towards standardizing taxonomic ranks using divergence times – a case study with Agaricus. Fungal Diversity. 78:239-292