The importance of population origin and environment on clonal and sexual reproduction in the alpine plant Geum reptans

1. Reproductive behaviour of plants may change in contrasting habitats. In two separate glasshouse experiments, we studied effects of population origin (early vs. late successional and low vs. high altitudinal habitats) and environmental effects (competition and temperature) on plant size and sexual vs. clonal reproduction in Geum reptans L. 2. Plant size and reproduction differed significantly among populations, but only plant size differed between contrasting habitats. 3. If plants grew with competition or at warm temperature, plant size and reproduction were reduced and more plants reproduced only with stolons. Individuals with flowers were larger than those that reproduced only with stolons, indicating a smaller minimum plant size for clonal than for sexual reproduction. 4. Populations of different origin changed little in their response to environmental treatments. Plants from early successional habitats tended to produce more flowers in the competition-free treatment, whereas in plants from late successional habitats the opposite was true. 5. The results indicate limited adaptation in reproductive behaviour to contrasting habitats. Nevertheless, great size-dependent plasticity in the proportion of sexual vs. clonal reproduction ensures population persistence and reproduction in a large range of habitat conditions.