Coastal Bluff Morning-Glory (Calystegia purpurata subsp. saxicola)
This photograph is from 14 May 2011, but 2013 also seems to be a very good year for this native perennial on Bodega Head.
P.S. The subspecies name "saxicola" means "rock-dwelling."
P.P.S. Calflora calls this species the Bodega Morning-Glory!