Fig. 2. The effect of four temperatures on the seedling dry mass per pot of tall fescue, sloughgrass, and tufted hairgrass grown in monoculture and in two-species mixtures at three mixture ratios. The relative crowding coefficient (RCC) for each pair of grasses (k_fb, tall fescue with sloughgrass; k_bf, sloughgrass with tall fescue; k_fd, tall fescue with tufted hairgrass; k_df, tufted hairgrass with tall fescue; k_bd, sloughgrass with tufted hairgrass; and k_db, tufted hairgrass with sloughgrass) grown in mixtures is shown. Lines with X indicate the combined species yields. All standard-error bars are smaller than the size of the symbols.