XVI International Botanical Congess

Polyploidy can have multiple consequences. A frequently evoked idea is that polyploids, by virtue of their high potential levels of individual heterozygosity, may have 'general purpose genotypes' capable of buffering environmental variation. The colonization of new environments would thus be faciltated by phenotypic plasticity that permits polyploids to maintain their relative fitness stable across environments. I examine these ideas by contrasting (1) the ecological amplitude of diploids and tetraploids across different genera in a single flora and (2) levels of plasticity of related diploids and tetraploids in relation to environmental variation. I find little evidence to support the idea that natural polyploids are less specialized than related diploids, and argue for local adaptation as an important component of the evolutionary success of natural polyploids.