Collection location: Los Trancos Preserve, Palo Alto, Santa Clara Co., California, USA [Click for map]
This was id’ed using the Northwest Key council key to Veined Mushrooms. Mostly from the lighter greys at the edge on these, and the more cup like shape instead of deaply lobed, and the attchment more towards the center on the back. But it could be A. lobata.
The real difference between the two is the presence/absence of clamp connections. Which probably I should better at trying to find at some point here. But if there are no clamp connections observed, then this id will stand.