Thoroughly referenced and generously illustrated, this book discusses all aspects of cycadology. A small group of ancient palmlike seed plants noted for their beautiful foliage and often brightly colored cones and seeds, cycads are believed to have been the first seed-bearing plants. Seed bearing was the basis for their worldwide dominance from about 300 million years ago to about 70 million years ago, when today's familiar flowering plants gained ascendancy. In recent years, interest in cycads has increased, partly as a result of the need for a more complete identification of the range of toxic and carcinogenic substances these plants produce and partly because of the recognition that some compounds from cycads may prove valuable in biomedical research.Many cycads have recently been identified as endangered species, including some that seem to have survived virtually unchanged since the Mesozoic era. Cycads have a specific importance, now at risk of being lost forever, for the information they offer on the origins and evolution of seed plants.Knut J. Norstog and Trevor J. Nicholls discuss cycad anatomy, reproduction, physiology, and growth. They also focus on population biology and the fossil cycadophytes as well as genera and species from both the Old World and the New World. The Biology of the Cycads is illustrated with numerous maps, diagrams, and drawings, as well as more than 350 photographs, in black and white and in color.