Fig. 3: Relationships of the community lineage means of stomatal traits for grasses versus non-grasses (with stomata with dumbbell- versus kidney-shaped guard cells, respectively) to the environment across 29 grassland sites.

CLM community lineage mean, SL stomatal length, SD stomatal density. PC1, PC2, and PC3 represent the first three axes of the Principal Component Analysis (PCA) for 30 environmental variables, respectively. a–c Relationships of CLM of SL to PC1, PC2, and PC3, respectively. d–f Relationships of CLM of SD to PC1, PC2, and PC3, respectively. Ordinary least squares regression was used to explore relationship between the CLM of stomatal traits and environment. The differences in regression slopes and intercepts were assessed using analysis of covariance (ANCOVA). The solid lines depict significant linear regressions and the dashed lines non-significant linear regression; the gray shading indicates 95% confidence intervals. 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. The p-value of <0.05 signifies significant differences in the slopes and intercepts of the relationships of stomatal traits for dumbbell-shaped and kidney-shaped guard cell stomatal types to the environment. For additional details, please refer to Table S6, 7. Source data are provided as a Source Data file.