Karyological and molecular studies were done in this paper on three species of genus Arum; Arum italicum Mill. and Arum maculatum L., with two varieties, and Arum alpinum Schott and Kotschy, also with two varieties. The main goal of this paper was to establish whether they were regularly determined exclusively on the principle of morphological parameters. Karyological studies showed that the number of chromosomes for Arum italicum Mill. amounted to 2n=84, for Arum maculatum L. 2n=56 and for Arum alpinum Schott and Kotschy 2n=28. This confirmed that these species are not only clean and separated, but also support the regularity of the morphological determination. Molecular studies, e.g. RAPD method showed that two genetically separated species groups correspond to the three mentioned species. Arum italicum Mill. is the least homogenous species closely related and the variability between populations is high. Arum maculatum L. is more homogenous within the species, two varieties could be differentiated whereas they are closely genetically related and the variability between the populations is too high. Arum alpinum is strongly homogenous and within these species two varieties could also be differentiated. That means that they are closely related and the variability between the populations is very high. These observations mostly coincided with previous morphological investigations.
Institut fur Systematische Botanik, Zollikerstrasse 107, CH - 8008 Zurich, Switzerland