I have found an Agaricus sp. at a touristic sand dune which I am trying to identify from the macro and micro.
- The mushroom has a cap 9 cm across and about 12cm long, stem 2 cm diameter. Odor fungoid (mushroomy), pleasant, like edible mushrooms, a hint of aromatic (but I don't mean anise-like). Taste like button mushrooms, slightly bitter.
- Ring fleshy but with a thin outer rim.
- Gills chocolate brown, crowded
- KOH -ve on flesh and cap
- On cutting in half there was no reaction but a little redding at the flesh under the gills and cuticle.
Spores size:
(5.5) 5.8 - 6.7 (16.6) × (4.3) 4.4 - 4.9 (5.2) µm
Q = (1.1) 1.2 - 1.4 (1.7) ; N = 39
Me = 6.5 × 4.7 µm; Qe = 1.3
Sterigmata x2 (+++) and x3 (+) and x4 (++) [ plusses = estimated abundance ]
Cheilocystidia not seen but maybe not distinct or deteriorated.
I would say it is an Agaricus bisporus with spores escaping from the restaurants closeby (from delivery of fresh button mushrooms), but the x3 and x4 sterigmata are a bit off for bisporus (or they can be found too?)