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 ofFestucawere analyzed by sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS–PAGE). The banding patterns for three species of rough fescues (sectionBreviaristataeKrivot) indicate that although the taxa are closely related,F.campestrisRydb. (2n = 56) does not appear to be an autoploid of eitherF.altaicaTrin. (2n = 28) orF.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 ofFestucaL. analyzed. The profile forF.californicaVasey, questionably sectionBreviaristatae, also has a band at this position, and is very different from that ofF.altaica,F.campestris, andF.hallii. Species-specific banding patterns were observed forF.brachyphyllaSchultes,F.saximontanaRydb.,F.idahoensisElmer, andF.trachyphylla(Hackel) Krajina (F.ovinaL. s.l.,F.longifoliaThuill.,F.ovinavar.duriusculaauct. amer.). The results support the recognition of subgenusSchedonorus(Beauv.) Peter., and sectionsBreviaristataeKrivot andFestuca.Key words: Poaceae,Festuca, SDS–PAGE seed proteins.