Medicinal plants in the California missions, and the 1812 survey that counted them

In 1812 the Alta California missions were asked, among much else, what plants the Indians used as medicine. Thirteen of eighteen answered that they used them; between them they named sixteen species. Native Californians had used around two hundred and sixty-five. The gap, and the eight reasons a modern study gives for it, are the most exact measure available of how much medical knowledge the mission system actually took in — and of how much it refused.