Comment: and that is all I claimed. Technically it could be A. pediades but I think it is equally likely to be something else. Irene noted another new species and I still like A. platysperma. It is a valid, recognized species from California. Besides the spores the cap description also works.
And in the framework of MO, if someone else has an opinion, He/she can vote and Mike Wood in this case tilted the argument in favor of A. platysperma. Not crazy, just Democracy in action.
Unfortunately, I did not save any specimens. I’m too old to start another career as an Agrocybe specialist.