This is the second volume of what will be a magnificent compendium of taxonomic information about the more than 17,000 species of plants that grow in the United States and Canada. Volume 2 presents taxonomic treatments for the pteridophytes and gymnosperms (whisk ferns, horsetails, clubmosses, ferns, cycads, ginkgos, conifers, and gnetophytes). As in the first volume, identification keys, summaries of habitats and geographic ranges, distribution maps, pertinent synonymies, descriptions, chromosome numbers, phenological information, and other significant details are given for each species. Line drawings are included for species with special morphological characteristics. Treatments are written and reviewed by distinguished experts in systematic botany and are based on original observations of herbarium specimens supplemented by critical reviews of the literature. The 12 volumes that will comprise this compendium are uniquely important in that no comprehensive flora of North America currently exists. This volume is an essential addition to the libraries of professional and amateur botanists and plant taxonomists.