California milkmaids
Cardamine californica
Brassicaceae

Um... oh boy, I got an eyeful as I tried to search for more information on this plant. Makes me wonder about the etymological relationship of the family name Brassicaceae with brassiere. I might add more information once I get the boobs out of my memory.

This plant is also known as bitter-cress or toothwort. There's a small section above the waterfall trail at Garland Ranch where I can always count on seeing this small white flower in February.