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For many years morphology was regarded as a basic discipline in the study of botany and, consequently, there have been many textbooks dealing with the subject. The pterido-phytes occupied varying proportions of these, and there were even some textbooks devoted to a single group, such as the ferns, within the pteridophytes. However, to the best of my knowledge, no book dealing solely with the pteridophytes has been pubHshed in the western hemisphere since 1936. Some of the old classics have recently been reprinted, but there is a need for a reappraisal of the old theories in the Ught of recent knowledge. Contrary to general behef, the study of morphology is a very live one, and many important advances have been made, on both sides of the Atlantic, in the last decade. Exciting new fossils have been discovered and new techniques have been developed for studying living organisms, to say nothing of the discovery of an entirely new genus of lycopods in the High Andes of Peru...