PREMISE OF THE STUDY: Studies of natural populations of polyploids increasingly highlight complex patterns of variation in ploidy and geographic distribution of cytotypes. As our understanding of the complexity of polyploidy grows, our understanding of the morphological correlates of polyploidy should expand as well. Here we examine in what ways, and to what degree, polyploidy aff ects the overall phenotype of a species across its distribution when there are three ploidies and geographic complexity in cytotype distribution. METHODS: We measured 31 morphological traits from stems, leaves, and fl owers from up to 25 individuals from 11 sites across the distribution of P hloxamabilis . Chromosome counts and fl ow cytometry confi rmed and expanded upon earlier research documenting diploid, tetraploid, and hexaploid populations, and also identifi ed a site with two ploidies. Univariate and multivariate statistics were used to characterize the morphological eff ects of polyploidy. KEY RESULTS: We detected signifi cant associations between morphology and ploidy in 11 traits spread across vegetative and reproductive structures. Generally, diploid individuals diff ered from polyploid individuals to a greater extent, and in diff erent ways, than tetraploid and hexaploid plants diff ered from each other. Multivariate morphometrics demonstrated that the two primary axes of overall variation are driven by morphological traits associated with polyploidy, and individuals of diff erent ploidies can be discriminated with 95% success.
CONCLUSIONS: Polyploidy plays a major role in shaping overall morphological diversity in natural populations of P . amabilis. KEY WORDS cytotypic variation; multivariate morphometrics; phenotypic diversity; Phlox ; plant morphology; Polemoniaceae; polyploidy
