This book has been prepared as a text to meet these needs as required by undergraduate and post graduate students of systematic botany. Its level of presentation is sufficiently elementary not to presuppose formal training in all of the allied botanical sciences, yet it does open channels to further study of them by those more advanced students who may have had the benefit of a considerable botanical background. This book represents several marked departures from existing works. The subject Matter is divided formally into two parts, Part One presents the more academic and theoretical considerations of taxonomy, supplemented by explanatory chapters of the practical fundamentals found to be essential to a minimum working knowledge of the science. Part Two is composed of a systematic enumeration of the 264 families of vascular plants.