The work offerred here is a companion volume to the work by K. FAEGRI and L. VAN DER PI]L "Principles of pollination ecology", which deals with the preceding phase of reproduction in plants. In the present work too, the emphasis is on principles and ecology. It is neither an enumeration of mechanisms, nor a compilation of cases. RIDLEY'S monumental work "The dispersal of plants throughout the world" already comprises 700 large pages of small print, and research has proceeded since then. Though this work is more than just 'a compilation and contains much insight and thoughts on principles in addition to reviews, its completeness hinders its use as a textbook. As a reference work, it is unsurpassed and the writer made frequent use of it. The writer paid special attention to functional backgrounds for the use of taxonomists working with "characters" and to biosystematics at the macro-level. He is indebted to Dr. P. MULLER-SCHNEIDER (Chur, Switzerland) for the permission to translate parts of his "Verbreitungsbiologie der Bliiten pflanzen" - of which permission a modest use has been made. Thanks are also due to 'the Director of the Rijksherbarium at Leyden, and to its librarian for the use of the library. Mr. F. J. NATAN was so kind as to make a number of photographs at the author's wishes.