The Cardamine species are known as Milkmaids.
They are among the first noticeable flowers appearing every Spring.
Not long ago I would have said this one was Cardamine californicum var. integrifolia (AKA the Coast Milkmaid; formerly Cardamine integrifolia) but apparently that species has been lumped and no longer exists except as Cardamine californicum.
Cardamine
Most of the year they look like this:
