Genomic constitutions of three taxa of Pseudoroegneria Á. Löve, P. geniculata, P. geniculata ssp. scythica, and P. geniculata ssp. pruinifera, were characterized using genomic in situ hybridization (GISH). The results indicated that ploidy level and genomic constitution in the three Pseudoroegneria taxa studied were as follows: P. geniculata (2n = 4x = 28; genomic formula StStg), P. geniculata ssp. scythica (2n = 4x = 28; genomic formula ESt), and P. geniculata ssp. pruinifera (2n = 6x = 42; genomic formula EESt). P. geniculata ssp. scythica and P. geniculata ssp. pruinifera should be transferred to Trichopyrum Á. Löve following Löve’s principles and treated as T. scythicum and T. pruiniferum, respectively.