Fig. 2: Changes in community lineage means of stomatal traits for stomata with dumbbell versus kidney-shaped guard cells and their relationships across 29 grassland sites.

CLM community lineage mean, SL stomatal length, SD stomatal density. a, b Differences in CLM of SL and SD between plants with dumbbell-shaped and kidney-shaped guard cell stomatal types, respectively. c, d Relationships of CLM of SL and SD between plants with dumbbell-shaped and kidney-shaped guard cell stomatal types across 29 grassland sites, respectively. Violin plots of stomatal traits for dumbbell-shaped and kidney-shaped guard cell stomatal types are filled with different colors. Two-sided paired sample t-tests were employed to investigate differences in stomatal traits between stomatal types. Ordinary least squares regression was used to explore relationship between the CLM of stomatal traits for dumbbell-type and kidney-type stomata. The solid and dashed lines depict significant and non-significant linear regressions, respectively, while the gray shading indicates the 95% confidence interval. We included the regression lines for both significant and non-significant relationships to allow for direct visual comparison of slopes and intercepts between the two groups. Source data are provided as a Source Data file.