North American <b>StStHH</b> tetraploid <i>Elymus</i> species.

1Plant introduction (PI) and W6 numbers were assigned by the USDA; RJMG and Barkworth accessions are from the first author and M. Barkworth, respectively. The E. trachycaulus accessions were collected in Canada; all others are from the United States. Voucher specimens are at ID. 2Numbers (#) distinguish individuals within species on Figures 1–3, S1. 3Letters identify cloned sequences from within each individual on Figures 1–3, S1. 4Dashes indicate individuals that were not sampled for the corresponding gene. 5NR: not recovered for a gene/individual. 6,7AY5532## accessions: [56]; AY0109## accessions: [29]; all others are new.