CYTOT AXONOMICAL STUDIES IN THE CHRYSANTHEMUM LEUCANTHEMUM COMPLEX

The Ox-eye Daisy is very polymorphic and a large number of infraspecific taxa have been described by various authors (see, e.g. Briquet & Cavillier, 1916, 86-88, and H orvatic, 1935). The polymorphy undoubtedly is most striking when material from various parts of the whole range is considered. In a small area like Denmark the variation appears to be moderate. In the years 1949-56, we have collected material in various European countries for experimental cultivation and chromosome studies. In this material we were able to confirm the euploid series of chromosome numbers, 2n = 18, 36 and 54 found by Dowrick (1952) in material from botanical gardens. The three cytotypes, however, apparently rarely occurred in the same area, suggesting three geographically distinct series of races. Dowrick (1952) states that there are no significant changes in form, apart from size and growth-rate, with increase in the degree of polyploidy and does not consider the cytotypes to be separate species. In our experiments, however, it is quite apparent that most diploids differ from the tetraploids in life-form (duration of life) and in some morphological characters. A taxonomic separation between the cytotypes, therefore, is not at all out of the question but an ex:haustive systemati