  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):
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:
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.” |
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