Systematics and Evolution of Seed Plants

Abstract

The main developments in systematics in the past two years have taken different directions. Firstly, the evolution of angiosperms documented by the combined fossil record of pollen and leaves led to a better knowledge of early forms of angiosperms and of the time of their first culmination. Secondly, the investigation of the evolution of repellent chemical compounds forced by animals as predators is a new field in chemical systematics. Still of interest and a field for unending discussion is the evolution of higher categories (symposium volume, ed. KUBITZKI, 1977a). Such subjects certainly are much more attractive to report and easier to present than results which appear mainly in “small print”; these are often very briefly mentioned but quite frequently contain the material for ideas which are discussed more broadly. So one could say that these subjects play the same role as the “small print” in contracts: points only briefly formulated but of major importance. One should not hesitate to see especially in revisions and, in general, in the increase of knowledge of the natural history of species and genera, one of the main aspects of progress in systematics. This is also the reason for presenting two chapters dedicated to special plant groups. The knowledge concerning the Compositae has increased stimulated by a Reading symposium (symposium volume, ed. HEYWOOD et al., 1977) and has led to many additional papers. But also the Apiaceae seemed to deserve special treatment. Certainly other groups too, e.g., the Leguminosae, with a good amount of special papers, and the Erythrina-symposium (ed. RAVEN, 19 77) could have been treated separately, but such a procedure would have led to another concept in this report.