With its Rocky Mountain foothills, hardwood forests, many rivers and streams, low mountains, sand dunes, cypress swamps, and wide swaths of rangeland and pastureland, the Great Plains state of Oklahoma is one of only four with more than ten ecoregions. Tallgrass, mixed-grass, and shortgrass prairies are native to large areas; rainfall and temperature are quite variable; and elevations drop from 5,000 to 300 feet. This diversity ensures that Oklahoma is host to hundreds of species of wildflowers, yet no guidebook to these botanical riches has been available in recent years. Patricia Folley's beautifully photographed and carefully compiled Guide to Oklahoma Wildflowers fills this gap. Folley has photographed and described the two hundred wildflower species that are most commonly seen along roadsides and in parks throughout the state. She provides at least two photos for each plant, showing the entire plant as it occurs in the wild, outside of cultivation, along with a close-up of its flower. Each plant is keyed to a particular geographical location and a particular family, and an index to colors is a further aid to identification. If a species is native-such as big bluestem, the defining grass of Oklahoma's tallgrass prairies-Folley presents this information in the text along with time of blooming, size and color of blooms, preferred habitat, and common and scientific names for all species. Oklahoma contains vast plains, elevated rocky plateaus, and forested mountains. Botanizing one's way across the Sooner State reveals celestial lilies in the east, prickly poppies in the west, Dutchman's breeches in the northeast, large-flowered evening primrose in central and southwest areas, Indian pink in the southeast, walking-stick cholla in the Panhandle, and purple prairie clover statewide. Gardeners, teachers, tourists, and naturalists of all levels of expertise will enjoy this guide's concise text and vibrant photos.