Biosystematic studies of the Rumex acetosella-complex II. The Alpine region

The present paper is a sequal to similar ones dealing with populations in Belgium and France. About 80 population samples were gathered in the following areas: the southern part of the German Federal Republic, the Swiss, Austrian and (partly) Italian Alps, and northern Austria. Of these samples the occurrence of angiocarpy vs. gymnocarpy and the chromosome numbers were determined, special attention being paid to the incidence of foliar multifidy. In the Alpine region proper the large majority of the individuals is gymnocarpic. In southern Germany and Lower Austria the plants are nearly always angiocarpic, however. The distribution of the levels of ploidy is rather intricate and roughly as follows: gymnocarpic diploids occur in the southernmost French Alps, in the southern and western Swiss Alps, and in a single population in the Austrian Wachau on the NE escarpment of the Alps; gymnocarpic tetraploids in the Austrian Alps, and rather numerous hexaploids, with some angiocarpy, in the intervening border area of the central Alps. In southern Germany and Lower Austria mostly angiocarpic hexaploids were encountered, with predominantly gymnocarpic tetraploids especially in the border area between Austria and Czechoslovakia (the Bohemian Forest). In the latter region hybridisation between tetra- and hexaploids frequently takes place. There are correlations between this chorological pattern and certain consistent phytogeographical phenomena in the Alpine region associated with its Pleistocene geological history, such as the presence of several refugia and the so-called Rein-Traun gap in the central Alps. In addition it is suspected that antropogenous influences have disturbed the original situation to an appreciable extent. The degree of dissection of the leaves, as a character included in the population analyses for the first time, is present to the same extent in alpine di- and tetraploids (in which the leaves are more or less multifid), but in the Alpine and the German and Lower Austrian hexaploids, foliar multifidy is hardly developed. Some possible causes and plausible conclusions are discussed. The single population in the Wachau refugium contains a singularly high percentage of plants with multifid foliage and this is, among other things, the reason why this population is considered to belong to a different population complex than do the Alpine ones. In the discussion some space is devoted to difficulties that may be expected if a future, novel taxonomic classification of the complex is attempted.