Taxonomically useful descriptors were provided by the banding patterns of seed storage proteins obtained when extracts of bulked, ungerminated seed samples from commercially available North American native species of Festuca were analyzed by sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS–PAGE). The banding patterns for three species of rough fescues (section Breviaristatae Krivot) indicate that although the taxa are closely related, F. campestris Rydb. (2n = 56) does not appear to be an autoploid of either F. altaica Trin. (2n = 28) or F. hallii (Vasey) Piper (2n = 28). A distinct band corresponding to a molecular weight of 57 000 occurred in the seed protein profiles of all native and commercial samples of Festuca L. analyzed. The profile for F. californica Vasey, questionably section Breviaristatae, also has a band at this position, and is very different from that of F. altaica, F. campestris, and F. hallii. Species-specific banding patterns were observed for F. brachyphylla Schultes, F. saximontana Rydb., F. idahoensis Elmer, and F. trachyphylla (Hackel) Krajina (F. ovina L. s.l., F. longifolia Thuill., F. ovina var. duriuscula auct. amer.). The results support the recognition of subgenus Schedonorus (Beauv.) Peter., and sections Breviaristatae Krivot and Festuca. Key words: Poaceae, Festuca, SDS–PAGE seed proteins.