A more detailed description of the populations included in the study with GPS coordinates can be found in Table 1 of the paper. The plant class column is as follows: DK EU = diffuse knapweed of European origin with no hybrids. DK NA = diffuse knapweed of North American origin with hybrids found in the population. DK UA = diffuse knapweed populations from the Ukraine with hybrids present. UA H was a hybrid swarm encountered in the Ukraine that was not included in the publication. SK = diploid spotted knapweed of European origin. BCC = the artificially created back cross lines (A, B, and C). Competition column: y = plant grown with western wheatgrass; n = plant grown alone; grass = the grass grown in the pot. The life history and morphological traits are fairly self-explanatory and explained in more detail in the paper and Table 2.