Appendix S1 - Plant Water Use Efficiency over Geological Time – Evolution of Leaf Stomata Configurations Affecting Plant Gas Exchange

Detailed presentation of the three different methods used to quantify the changes in stomatal density, d, and size, s with atmospheric CO2 concentrations during the Phanerozoic eon based on fossil record. These three methods led to the three curves depicted in Fig. 1a describing the resulting (s⋅d) evolution during the Phanerozoic. (DOCX)