HYBRIDIZATION BETWEEN ASTER AND MACHAERANTHERA AND ITS TAXONOMIC SIGNIFICANCE

A controlled crossing program resulted in the production of four interspecific and three intergeneric hybrids among species of Aster sect. Oxytripolium and Machaeranthera. Meiotic analysis revealed stronger degrees of genome homology in some of the intergeneric hybrids than in some of the interspecific hybrids. The significance of these results to the taxonomy of Aster and Machaeranthera was considered and the result was the transfer of Aster sonorae to Machaeranthera.