Field mushroom
Agaricus ?bisporus
An informal survey of the plant and animal life living in or visiting the grounds of Pointfield, Kelso since 2015
Fungi
Cap flattened, thick-fleshed with white flesh but with a thin fibrillose surface of reddish-brown mesh (only seen in undamaged areas). 12 cm in diameter. Edges of disc in small fresh form with veil remnants. Gills greyish brown to mid-brown turning black with age; dense, unbranched; free. Stem thick to 9cm in length and 23mm in diameter; shaggy in upper part, more fibrillose towards base, with thickened ring about half-way down that includes a downward drooping flap; base without roots and only very slightly expanded. Stem staining to a brownish red when cut or damaged. Spore print dark brown. Spores brown and rather thick-walled, small and rounded-ellipsoidal with asymmetric nipple and no germ-pore; Pore size 6.1-7.6 x 4.7-6.3 um (mean = 6.6 x 5.1 um, n = 25). Cystidea present; clavate. Basidia difficult to see clearly but apparently 2-spored.
Growing up through grass cuttings heap and already badly eaten before emerging.