Functional traits are a critical tool in sub-disciplines ranging from community ecology to ecophysiology to vegetation modeling, yet we know surprisingly little about trait variation within individual species. We use within-species or intraspecific trait variation to determine how plants build a stress resistant phenotype (for instance at their dry geographic range boundary). Trait variation within species can challenge foundational theories of trait integration and plant physiology, and can yeild unique inferences about biogeographic and population processes.
