This is a Lomatium dissectum. For the sake of context, I've been looking for a "chocolate lomatium" (common name) for years, unsuccessfully. I have seen them in leaf and in seed, but never in bloom, so this was very exciting. I might go back to get a few seeds (just a few) later on. When I was a botany major, Lomatiums were of special interest. There is still a lot to be learned about them, especially in terms of classification.