In Volume 2, over 50 contributors exhaustively describe and classify the ferns, fern allies, and gymnosperms of North America. Covering over two dozen fern and half a dozen gymnosperm families, they survey fern species of both ecological and horticultural importance and review such gymnosperm taxa as the conifers--the dominant trees in many forests as well as important timber plants--and cycads, which display significant evolutionary features. In all, the volume assembles 509 species of ferns and fern allies and infraspecific taxa in 70 genera. The editors have revised nearly 80 of these taxa to reflect classification changes since publication of the last standard work on ferns in North America. The gymnosperm treatments encompass 118 species in 22 genera. Identification keys, summaries of habitats and geographic ranges, pertinent synonymies, descriptions, chromosome numbers, and all other significant details are provided. More than 600 distribution maps and 65 illustration plates appear throughout.