It is the ellipsoid, finely punctate spores (I believe, might have to check that…), with the white fibrous cap surface, and non-hygrophanous. There are actually a bunch of Crepidotus with this, from the Smith and Hesler monograph say (it was Smith and Hesler for that one, yes?), but they were synonymized in the Italian Crepidotus book from 2009, by… I forget his name right now… but it is good book.
I used a different name in the past, I forget what, but I moved to the new name after getting that book. There are other white Crepidotus out there, but I believe in California, not with the ellipsoid finely punctate spores.