Collection location: Foothill Regional Park, Windsor, California, USA [Click for map]
This seems an unlikely ID in oak woodland. It was already free so I have no idea where it actually fruited. Found at the edge of the park near homes, so it might have been carried? If there’s something more appropriate to the surroundings, I was unable to find it. Pileus was 9.5cm across, and the stipe was 2.4cm at the apex and 4cm tall.
T. manzanitae is a good fit, I think. Thanks, Nathan.