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Hydrogen and carbon isotope ratios of terrestrial plant leaf wax are powerful paleoclimate and paleoenvironmental proxies. However, further research on the underlying controls of the chemical and isotopic composition is needed in order to more quantitatively infer past climate and environmental conditions. There are systematic molecular and isotopic trends along leaves of a C₄ grass Miscanthus, but whether such patterns also occur in other plant types is unclear. Here we determined intra-leaf variability in leaf wax abundance and isotope ratios for five terrestrial C₃ plants. All species showed a general increasing base-to-tip trend in leaf wax abundance, suggesting a physiological need for more leaf wax in outer leaf sections. The hydrogen isotope values showed base-to-tip deuterium enrichment in all plants, but carbon isotope values showed base-to-tip ¹³C depletion in most species. Such intra-leaf isotopic …