Fig. 3.

Validation of clines observed in the VCG. Standardized estimates (Z-score) of mean phenological development time ($\overline{\psi }$) were inferred from contemporary herbarium specimens from eastern North America, binned by 1° of latitude (green circles). This cline is similar to average Z-scores of flowering times measured for six populations grown at each of three reciprocal transplant sites spanning 10° of latitude: TIM (north, blue triangles), KSR (purple triangles), and BEF (south, red triangles).