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Symphytum officinale L. (Fig. 1) and Symphytum asperum L. (Boraginaceae) are allopatric taxa, which are able to intercross and to form interspecific hybrids with different chromosome numbers. The species differ not only in a number of morphological characters but also ecologically, S. asperum being a species of higher elevations (upper montane zone), S. officinale of lowland and the lower montane zone. S. asperum is a Caucasian species, which has the sporophytic chromosome number 2n = 32. It was introduced from the Caucasus into Europe as a fodder plant. S. officinale is variable, containing cytotypes with 2n = 24, 48, 56, 40, and occurs throughout Europe. |
