| Abstract: | Abstract A hypothesis on the evolution of Limonium species in the Mediterranean area. — The chromosomic somatic number of 27 species and 2 hybrids belonging to the genus Limonium (Plumbaginaceae) of several Mediterranean regions (Spain, France, Tuscany, Sardinia, Sicily) and Canarian Islands are here determined on wild populations. Keeping into account 10 data previously determined by other Authors, the chromosomic number is now known for more than 1/3 of the species occurring in West Europe and Mediterranean. This allows to formulate a hypothesis on the group's evolution: from some diploid species living on inner rocks (Felsenheide) or sea cliffs and having a very restricted area, tetraploid races living on sandy shores had developped, which expanded afterwards on the whole Mediterranean area, and finally by hybridations giving rise to triploids. Ecology and areal dimension of triploid species are generally intermediate between those of diploids and tetraploids; in some cases there is an apparent tendency to fragmentation into local forms, sometimes joined with apomictic reproduction. |
