We tested for ecological differences among apomictic dandelion genotypes in Vancouver, British Columbia, Canada, in order to establish a basis for predicting potential ecological consequences of genetic variation in invading populations. A greenhouse experiment on 30 potential clonal families revealed significant among-family variation for leaf morphological traits, and molecular analyses confirmed the presence of multiple genotypes. In a field common-garden experiment on six confirmed genotypes, plant size and seed production both varied over an order of magnitude among genotypes, suggesting great potential for selection among genotypes during invasion. Genotypes also varied significantly in the timing of reproduction, which may indicate differences in the timing of resource use that could promote population performance of genotype mixtures. There was no evidence of a trade-off between adult plant fitness and seed dispersal or regeneration traits. Genetic variation in dandelion populations appears to have great potential for influencing their invasive success.

Nomenclature: Dandelion, Taraxacum officinale Weber in Wiggers.