Flora of North America Volume 7 is the seventh volume of nineteen on dicotyledons to be published in the Flora of North America series. It treats more than 910 species classified among 114 genera in five families in the following two orders of the subclass Dilleniidae: Salicales (Willow order) and Capparales (Caper order). The families covered in Volume 7 include Salicaceae, Capparaceae, Brassicaceae, Moringaceae, and Resedaceae. Each genus has
representative species illustrated with a line drawing that, in combination with keys and descriptions, will facilitate identifications of these groups of plants. Even though many genera of mustards (Brassicaceae-nearly 100 genera with c. 750 species) are known in the flora area due to introduced species, many quite
species-rich genera-Draba (140 species), Boechera (109 spp.), Physaria (90 spp.), Lepidium (40 spp.), Streptanthus (33 spp.), and Rorippa (23 spp.)-have many endemic species that are known from quite restricted areas within North America.
The volume includes identification keys, descriptions, line drawings, and ecological characteristics for each of the species; distribution maps for the native and established species; and a list of the synonyms currently in use for the accepted names. The treatments, each of which has been extensively reviewed, are based on a combination of original observations and critical review of the literature.