Vascular Plants of the Pacific Northwest, in five parts, offers the first complete guide, with keys, to the ferns, fern-related, and seed-bearing plants of Washington, northern Oregon, Idaho north of the Snake River plains, the mountainous western part of Montana, and southern British Columbia. Each volume gives complete regional synonymy, type collections, geographic ranges, genuine common names, and chromosome numbers for each species, as well as economic importance and horticultural features.

Part 5 is a comprehensive guide to the composites of the Pacific Northwest, with emphasis upon the biology of the species. Attention is given to an ecological view of the species, emphasizing the concept of interaction of environment and plant population and the evolution within the latter of distinct ‘ecotypes.’

Part 5 is illustrated by John H. Rumely. All other volumes are illustrated by Jeanne R. Janish.