Collection location: Redwood National Park, Orick, California, USA [Click for map]
Or, I think more correctly these are Cystolepiota seminuda. In the wild these were covered with a small dusting of flakes, but those came off pretty quickly. These are really small guys, only 1 cm wide at the largest cap here. The partial veil remanants hang from the margins of the cap, and often I saw in the wild, the veil fragments would be pointing straight up from the margins. Including the flakes on the cap, it gave these a pretty strange look.