Cytotaxonomic studies in the genus Symphytum.II. Crossing experiments between Symphytum officinale L. and Symphytum asperum Lepech.

Crossing experiments were carried out between the three cytotypes (2n=24, 2n=40 and 2n=48) of Symphytum officinale and that of Symphytum asperum (2n=32). The results indicate that morphologically closely related types are sometimes crossable, whereas in other cases no hybrids could be produced. On the other hand morphologically very distinct types could be crossed with great ease. The significance of these studies for the elucidation of taxonomic problems is discussed.