In this book we are going to introduce something new and interesting to many, the weird cactus plant life of the Southwestern desert—strange and marvelous growths which we call the Fantastic Clan; and to increase the reality and charm of the subject we will take an imaginary trip into the domain of the flowers of the desert. We shall explain here how to come to know them, and how to grow them in gardens; and we hope that, after reading, you will desire to have a cactus garden of your own, for the desert cacti are so different and so beautiful, with their symmetry of filigree and lacework, their fantastic shapes and marvelous colorings, and in many cases with a perfection of design that seems to have just come from the draughting board. We will not attempt to picture _all_ the wondrous beauty of the Night Blooming Cereus, nor to tell how dainty the Arizona Rainbow and the California Pincushion really are. We will try, however, to treat in large measure about them, and about all the most important groups of cacti known to man, here in Mexico and our own Southwest, the great cactus area of the earth. We will show where they live and how they live, and in what manner they grow; and when you actually see them, in traveling across the Great American Desert, you will appreciate the wondrous beauty of desert creations and the flashes of brilliant color, gorgeous beyond description. No artist can paint nor pen describe the weird Fantastic Clan, as they are glimpsed peering out from under the rocks or gathered in clusters and patches surrounded with their dead-looking, drab-colored neighbors; or rearing their stately heads far above the ordinary walks of life in columnar pillars of towering strength. There is a fascination away out there on the desert; nevertheless, unlike the strange weird members of the cactus clan, we come not to stay, but only to enjoy the charm of the desert, to study and learn, and then to depart on our way. Without help from the following persons and organizations, it would have been impossible for us to make such careful study of these plants, so widely distributed over the Southwestern deserts: We thank Dr. James Greenlief Brown and Dr. Rubert Burley Streets of the University of Arizona for numerous photographs; Professor Andrew Alexander Nichol of the University of Arizona for rare species of cacti collected; Dr. Forrest Shreve of the Carnegie Institution of Washington for specimens of plants and photographs; Evelyn Thornber for pen-and-ink drawings of cacti; Miss Frances Hamilton, Mr. William Palmer Stockwell, Mr. Frank Henry Parker, and Mr. Barnard Hendricks for assistance in making careful studies of the cacti; the University of Arizona and the Desert Botanical Laboratory of the Carnegie Institution for help in procuring specimens of cacti for comparative study. We are deeply indebted to Mrs. John Wilmot Estill of Los Angeles, California, for her exquisite paintings used in this book.