Flowering Plants and Ferns of Arizona

Arizona ranks very high among the States in the richness and diversity of its flora. Approximately 3,200 species of flowering plants and ferns, growing without cultivation, are known to occur within its limits. Many other species have been collected so near the borders of Arizona that they are almost certain to be found in the State. It therefore seems appropriate that the United States Department of Agriculture should undertake publication of a flora of Arizona.