San Francisco hosts two of the rarest manzanitas in the world: Raven's Manzanita (Arctostaphylos montana subsp. ravenii) and Franciscan Manzanita (Arctostaphylos franciscana). These endangered species grew together in a distinct maritime chaparral habitat that once covered the serpentine hilltops of San Francisco. Their story is one of discovery, loss, salvage, and restoration, with a bit...