Agaricus bisporus (J. Lange) Pilát Common mushroom
Cap: width 40-100 mm. Stem: width 15-25 mm; length 50-75 mm.
Description: [Plate 43].
Cap: rounded gradually expanding to become plane, whitish with numerous brown radiating fibrils and with the margin irregular because of fragments from the ring which are left there after expansion of the cap.
Stem: short, cylindrical, smooth, bruising reddish-brown when handled and with a narrow ring which soon collapses and disappears.
Gills: free, pink at first then purple-brown, narrow and crowded.
Flesh: solid, thick, firm and slowly flushing brownish on cutting.
Spore-print: purple-brown.
Spores: medium-sized, broadly ellipsoid, purple-brown under the microscope, less than 10 µm long, (6-8 × 5-6 µm).
Marginal cystidia: club-shaped, 10-12 µm at apex.