1. Chihuahuan Desert: Lechuguilla (_Agave lechuguilla_); 2. Sonoran Desert: Saguaro (_Carnegiea gigantea_); 3. Mohave-Colorado Desert: Joshua-tree (_Yucca brevifolia_); 4. Great Basin Desert: Sagebrush (_Artemisia tridentata_). This publication deals with the common plants and flowers of the Chihuahuan, Sonoran, and Mohave-Colorado Deserts. Since these names are strange to many visitors to the Southwest, the writer has taken the liberty of applying descriptive names as synonyms. In this booklet the Chihuahuan Desert is called the Texas Desert, the Sonoran Desert is referred to as the Arizona Desert, and the Colorado-Mohave Desert is considered as the California Desert. Whenever possible, the desert in which a particular species of plant is most common is indicated; however, this should not be interpreted too rigidly as most of the plants in this book grow in more than one desert and some grow in all. Because the Great Basin Desert is a region of higher elevation and is influenced by other factors which are not common to the three portions of the Great American Desert covered in this booklet, its vegetation is more like that of the plateaulands and foothills of the Southwest. Therefore, the flowers of the Great Basin Desert are included in a companion booklet, Polly Patraw’s “Flowers of the Southwest Mesas.” NATIONAL PARKS AND MONUMENTS AS WILDFLOWER SANCTUARIES Someone has called National Parks and Monuments “The Crown Jewels of America.” A part of their beauty and irreplaceable value is because the approximately 180 units of the National Park System which extends from Florida to Alaska and from Hawaii to Maine, are and have been wildflower sanctuaries. Not only do native plants live under natural conditions, but they are protected from picking, from grazing of domestic livestock, and from the competition of exotic species, and from other activities of mankind that would disrupt their normal habitat or disturb their native way of life. Men in the uniform of the National Park Service feel complimented whenever visitors show an interest in the natural features of the areas they protect, and are happy to assist them in locating rare species or especially beautiful or spectacular specimens. Range and grazing specialists are more and more using the natural vegetation of National Parks and Monuments as “check plots” to aid them in studying ways and means of preserving the level of grazing value on the open ranges.