Abstract
This study was undertaken for the purpose of determining whether there is any relationship between polyploidy and geographic distribution with special reference to species extraneous in a given area. It has been maintained that a more rigorous habitat tends to produce polyploids, that plants which are on the limits of their geographic distribution in a given area should exhibit a high degree of polyploidy since they are on one of the extremes of their habitat range. Since polyploids (particularly tetraploids) usually exhibit a greater vigor and adaptability than do diploids, it has seemed a natural deduction that diploid species might tend to give rise to polyploid races where the habitat had become more rigorous than the optimum for that species. To determine whether or not such a relationship exists among extraneous Indiana species, all such extraneous species which have been studied cytologically were tabulated.
