ECOLOGICAL ASPECTS OF FLOWER EVOLUTION. II. ZOOPHILOUS FLOWER CLASSES

For a century botanists have tried to construct schemes to classify flowers apart from taxonomy. As quite a number of parameters (forms, diverse functions, visitors) had to be reckoned with, all the systems are more or less one-sided. Werth (1915, 1956) objected to the vagueness of Delpino's ecological classes (according to pollinators), which "only comprise the extremes" and pointed to their structural diversity. He therefore promoted the use of structural types (Bautypen) of a supposed autonomous, morphological nature and showed the emerging of higher types during geological periods. What is pure form to one man is, however, crystallized function to another. The structural types are not independent of pollination, as shown above (cf. Leppik), and as admitted incidentally by Werth. The exclusive use of "morphological" types, according to the way of pollen deposition, splits natural entities and leaves some clear and natural ecological classes in the cold. Therefore, Werth has to discuss hydrophiles, anemophiles, pollen flowers, sapromyophilous traps, etc., separately in a large part of the book. The convergence in sapromyophilous flowers is ascribed (p. 92, 123) to "einem zielgerichteten Sckopfungswillen" (finalistic creation). Here I will try to revive interest in the classes according to the visitors-classes with bad boundaries, but with a clear center, foci of differentiation in different substrata but leading to convergence, a style. Acquaintance with them may shed light on evolutionary processes in the past and peculiar forms in the present. I shall, of course, not try to give a complete review but shall make a selection in the direction of dynamics. CANTHAROPHILY (POLLINATION BY BEETLES)