Fig 3. Flowering potential for plant functional groups.

Mean (± SE) flowering potential (FP), the relative cover of species expected to flower in each month of the prairie growing season. FP for forb (top) and C₃ graminoid (middle) functional groups are averaged across all prairie ecoregions, as the highest order interaction for these was nitrogen (N) * month. C₄ graminoid FP (bottom) is provided for the tall-, mixed-, and short-grass prairies as there was an N * month * ecoregion interaction for this group. Asterisks indicate values that are statistically distinct *** p < 0.001, ** p < 0.01, *p < 0.05 (Bonferroni corrected).