Since this booklet was written by a layman for the use and enjoyment of other laymen, it violates a number of botanical, or taxonomic, principles. These violations have been committed with no spirit of disrespect, but in an effort to avoid confusion, conserve space, and keep a complicated and involved subject as simple as possible. The writer believes that the visitor to the desert who has a normal pleasure in nature is interested in the flowers because of their beauty and their relationships with other inhabitants of the desert, including mankind. THE DESERT—WHAT AND WHERE IS IT? In this booklet we are dealing with DESERT flowers, so it seems logical to take a moment to check upon the desert itself. What is a desert, and how may we recognize one when we see it? “A desert,” stated the late Dr. Forrest Shreve, “is a region of deficient and uncertain rainfall.” Where moisture is deficient and uncertain, only such plants survive as are able to endure long periods of extreme drought. Desert vegetation is, therefore, made up of plants which, through various specialized body structures, can survive conditions of severe drought. In general, the deserts of the world are fairly close to the equator, so they occur in climates that are hot as well as dry. Plants in the deserts of the Southwest must endure long periods of heat as well as drought. In North America, major desert areas are located in the general vicinity of the international boundary between Mexico and the United States. Due to various differences in elevation, climatic conditions, and other factors, certain portions of this Great American Desert favor the growth of plants of certain types. Based on these general vegetative types, botanists have catalogued the Great American Desert into four divisions, as follows (see map): 1. Chihuahuan Desert: Western Texas, southern New Mexico, and the Mexican states of Chihuahua and Coahuila. 2. Sonoran Desert (Arizona Desert): Baja (Lower) California, northern Sonora, and southern Arizona. 3. Mohave-Colorado Desert (California Desert): Portions of southern California, southern Nevada, and northwestern Arizona. 4. Great Basin Desert: The Great Basin area of Nevada, Utah, and northeastern Arizona. It is of especial interest to note that certain plants such as Creosotebush (_Larrea tridentata_) seems to thrive in several of these desert areas while others are found in great abundance in only one. Plants that grow in profusion in only one desert are spoken of as “indicators” of that particular desert. Any person interested in desert vegetation soon learns the major indicators, not only of the different deserts, but of different sections or elevations in the same desert. Here are some of the better-known indicator plants: