Is there evidence for rapid adaptive evolution in invasive populations of purple. There must be adaptation to local growing the map is a time course of invasion as the plant moves north environments. They could be doing this through phenotypic plasticity, and there may not actually be genetic variation. (recall phenotype vs genotype). We can perform a common garden experiment: collecting seeds from all the populations, then germinating them in one environment. Here, we allow the genes to express their phenotypes in a single environment, so we can disentangle the effect of the environment from the effect of the genes. Then, we measure the traits and make predictions that the plants growing south should grow bigger (larger growing season) and delay flowering (until the plant is larger to produce hundreds of flowers). There is no adaptive significance to growing early when the adaptive season is long.