Flora of North America, Volume 3, provides information on many of the most familiar wildflowers and trees in North America. Included are treatments of the buttercup family (Ranunculacaeae), with such plants as delphiniums and columbines, and the poppy family (Papveraceae). Most of the important broadleaf tree species are covered, including the oaks (Fagaceae), elms (Ulmaceae), birches (Betulaceae), walnuts (Juglandaceae), plane trees (Plantanaceae), and magnolias (Magnoliaceae). Many striking families are covered, such as the dutchman's pipe family (Aristochiaceae), and the aquatic families Nymphaeceae (water lilies), and Melumbonaceae (lotus).

Identification keys, summaries of habitats and geographic ranges, distribution maps, pertinent synonymies, descriptions, chromosome numbers, phenological information, and other significant biological observations are given for each species. The treatments, written and reviewed by experts throughout the systematic botanical community, are based on original observations of herbarium specimens, and wherever possible, on living plants. These observations are supplemented by critical reviews of the literature.