California cudweed
Gnaphalium californicum (aka Pseudognaphalium californicum)
Asteraceae

It's always fun finding a new plant that I have absolutely no idea what it is. Thanks to Rooted in California, I got a lead and looked into it. This plant is also called California everlasting or ladies' tobacco and can also be found under the genus Gnaphalium - maybe those who are in the know believe this isn't a real cudweed by adding pseudo. Simply based on online photos, the flower is superficially similar to pearly everlasting (Anaphalis margaritacea). I wonder if many online pictures are misidentified which creates some confusion for a novice like me. I do think this cudweed can be distinguished from pearly everlasting by the distinctive way how the leaf bases wrap around the stems and the slightly pointier buds.

ps 07/25/11 - As I've looked into a new post, Gnaphalium is the name used on Calflora.org. I haven't quite figured out why Jepson online is different from the 2nd edition in its acceptance of Pseudognaphalium as an alternative. In any case, I edited the scientific name above to include both possibilities.