Seventeen grass species and two forbs, planted on a minimal Chestnut soil in northern Nevada, were grown under various degrees of competition in the native shrub, Artemisia tridentata, for 18 years. Grass species included seven native bunchgrasses, six exotic bunchgrasses, one native sodformer, and three exotic sodformers. Forbs gave no persistent stands. Performance of native bunchgrasses was poor. The surviving exotic bunchgrass, Agrophyron desertorum, A. elongatum, and Elymus junceus, rated fair, poor, and good, respectively, after 18 years. These three species produced well for 11 years, after which yields declined sharply. As a group the sodforming agropyrons, Agropyron intermedium, A. trichophorum, and A. smithii, performed better than did the bunchgrasses. The greatest production of Bromus tectorum was on plots that had failed after 5 years or where species were not well adapted to the site. Only scanty B. tectorum grew on plots of A. intermedium and A. trichophorum. When re—invasion by Artemisia tridentata occurred, greatest brush numbers were found on plots of species that failed early in the study and on plots where seeded species failed after 5 years. The sodforming agropyrons were most effective in preventing shrub re—invasion. The ability of Agrophyron intermedium, A. Smithii, and A. trichophorum, especially the latter, to establish readily, to suppress brush and annual grass invasion to produce superior yields, and to spred vegetatively under considerable precipitation fluctuation and brush competition indicates the adaptability, aggressiveness, and competitive strength of these sodformers.