To others who have generously sent material of various species, and to the directors of the numerous botanical gardens who have generously sent seeds of many species, we also wish to express our gratitude. We are also much indebted to Mr. Ernest Jund for valuable assistance in growing the cultures and in making the cyto logical preparations, and to the Park Naturalist, Yosemite National Park, and his assistants for their generous cooperation in germinating the seeds of the more difficult species.