Grasses are an integral component of almost all terrestrial ecosystems, both natural and artificial. In some areas they are conspicuous, dominating the vegetation over large areas; in others, they are easily overlooked, our eyes being drawn first to trees, shrubs, and colorful flowers. Nevertheless, they are, in many respects, the world`s most successful plants, growing from tropical rain forests to arctic tundra, from ocean beaches to freshwater streams and lakes, and from strongly saline to strongly acidic soils. Their success can be attributed to many factors, not least the ability of pooid grasses to grow in cold climates, a remarkable achievement for plants whose ancestors evolved in tropical forests. Other lineages are more conspicuous in warm climates, the andropogonoid grasses that are most abundant in areas with a monsoonal climate, and panicoid grasses that flourish in warm climates with more or less evenly distributed rainfall.

The Intermountain Region is home to all these groups and a few others, but it is the pooid and chloridoid grasses that predominate, the former being most abundant in the north and at high elevations, the latter in the south and at lower elevations. This book provides descriptions, identification keys, illustrations, and distribution maps for more than 480 grass species in the region, including native, introduced, and cultivated species.