Many of the St-genome polyploids in the Triticeae.
In a genomic system of classification, Elymus generally includes all of the StH, StY, StHY, StWY, and StPY tetraploids and hexaploids. The StHNsNs octoploid is classified as Pascopyrum. The E and/or J combinations are usually classified as Thinopyrum. (Many authors place J- and E-genome species in Thinopyrum, i.e., do not recognize Lophopyrum as a distinct genus.)