Book excerpt: To be published in 14 volumes over the next 12 years, this long-awaited synoptic compendium represents the first and only comprehensive taxonomic guide to the extraordinary diversity of plant life blanketing our continent north of Mexico--including Greenland and the St. Pierre and Miquelon islands. The collaborative effort of more than 30 major U.S. and Canadian botanical institutions, it revises and synthesizes literally thousands of floristic monographs and regional floras published over the last three centuries. But more than that, it distills the original herbarium, laboratory, and field work of hundreds of contributors--all of them leading botanists and taxonomic authorities who have joined forces to develop this century's premier tool for identifying, understanding, and conserving North America's priceless floristic heritage. Concise, easy to use, and beautifully bound and illustrated, Flora of North America is an indispensable working resource for botanists, conservationists, ecologists, agronomists, foresters, range and land managers, horticulturists,--anyone with a serious interest in the distribution, habitat, morphology, and survival of the wide-ranging plant life around us. Each of its taxonomic volumes brings together the full spectrum of critical botanical data, from basic descriptions to chromosome numbers. The entries also correct erroneous information, qualify misapplied variant names, and note known hybridizations. Findings derived from recent experimental work and from numerical taxonomy are incorporated, and to assure accuracy, these data have been extensively reviewed and tested by cooperating taxonomic specialists. Volume 1 consists of a series of introductory essays by nearly two dozen noted botanical authorities. Among the topics covered are the transformation of North American plant life since the end of the Mesozoic era some 70 million years ago; the influence of geographic, climatic, and soil factors; the impact of human cultivation; great naturalists and their contributions to botany and floristics since the age of Columbus; and approaches to plant classification, with particular attention to the evolutionarily unique pteridophytes and gymnosperms that are covered in Volume 2.