Book excerpt: Field Guide to the Grasses of Oregon and Washington is an illustrated guide to all 376 species, subspecies, and varieties of grasses--both native and introduced--that grow wild in Oregon and Washington. It also has broad applicability in neighboring states and provinces. Grasses are important functional components in a variety of ecosystems and are highly valued for habitat restoration in numerous habitats, ranging from wetlands to deserts, and from sea level to alpine. They are important weeds and are also cultivated as ornamentals. This guide covers the entire spectrum of grasses from weedy invaders to rare native species. Identifying grasses can be challenging. The grass family is one of the most diverse plant families in the region, and differences between species can be both subtle and minute. This guide provides identification keys, species descriptions, photographs of each species (both in the field and through a microscope), habitats, and range maps. Users will especially appreciate the macrophotographs that illustrate hard-to-see, diagnostic features. Biologists, land managers, botanists, and consultants, as well as plant professionals, home gardeners, and amateur plant enthusiasts, will find this guide an indispensable reference for identifying all the grasses they encounter in the diverse habitats of Oregon and Washington.