Abstract
Populations of diploid F. pratensis and tetraploid F. pratensis var. apennina were collected from 12 locations in the Swiss and Italian Alps. Tetraploid F. pratensis var. apennina was found only at altitudes of 1500 m in Switzerland and 1100 m in Italy. The 2 forms occurred together in woodlands at altitudes of 1500-1700 m in Switzerland and 1100-1600 m in Italy. F. pratensis var. apennina had a cold requirement for germination which was not present in diploid F. pratensis. F. pratensis var. apennina seedlings were much more cold-susceptible than diploid F. pratensis. A model is described which shows that seed dormancy and seedling cold hardiness could be the critical factors affecting the survival of these cytotypes in their typical habitats.