It was apparent in the field this was an Oenothera. From the location and the visible characters...and in particular the distinctive form of the tubercled fruits seen here (which Isaac found reminiscent of ''sea cucumbers'' ;-)...this appears to be O. cespitosa ssp. marginata. The Jepson eFlora key emphasizes fruit characters and leads there, with their line drawings appearing to be a good match...as is Fig. 52A on pg. 146 of Wagner, Hoch, & Raven(2007), as well as the visible fruits in the specimen images here and here. And there's a collection record from nearby.

Considering how important fruits are for distinguishing taxa in the 'O. cespitosa group' (and other members of the genus), it's somewhat surprising that so relatively few fruit images currently appear on CalPhotos. However, there is a nice 'fresh' fruit image for the annual O. caverna...which is a member of the 'cespitosa group' that is locally endemic to the Clark Mountains.