Systematics and morphology

Hexaploid tall fescue [Lolium arundinaceum (Schreb.) Darbysh. = Schedonorus arundinaceus (Schreb.) Dumort., formerly Festuca arundinacea Schreb. var. arundinacea] is an agronomically vital member of the grass family that has been characterized based on morphological characteristics, interfertility relationships, and, more recently, genetic criteria such as gene sequences. Efforts to improve tall fescue for forage or turf and to gain insight into processes of grass evolution hinge on an accurate depiction of the interrelationships that exist between this species and other Lolium and Festuca grasses. The evolution of hexaploid tall fescue, and a majority of grasses, has involved interspecific hybridization that obscures species boundaries but, more importantly, serves as a rapid means of combining distinct genomes into novel progeny with enhanced evolutionary potential. We discuss here the systematics of the Festuca-Lolium complex within the context of such processes and highlight the dynamic and often confounding evolutionary history that characterizes tall fescue and its relatives.