In spite of the importance of phosphorus (P) to plant physiological function and growth, relatively few studies have quantified foliar P fractions in native plants in natural environments. Understanding how these P fractions vary with P availability, soil type and parent material should provide information on the importance of P storage versus its partitioning to cell ultrastructure versus active biochemical compounds. In the latest study evaluating foliar P fractions, McQuillan et al. (2020), this issue, have enlisted a novel technique to estimate these foliar P fractions for major groups of functional and structural compounds in native species of different taxa across sites west of the Great Dividing Range of Australia. Combined with recent studies of diverse tropical species, there is a conservative amount of lipid-membrane P and nucleic acid P across a threefold range of leaf P concentrations, from very low leaf P concentration to what could arguably be considered moderately low leaf P concentrations (0.3 to 1.0 mg g−1 leaf P concentration). The findings provide insight into how overall leaf P concentrations are partitioned, including that P investment in structural components of the leaf like membrane phospholipids is remarkably conservatively regulated. Further insights await a quantification of organelle-specific P fractions on well-preserved samples, so importance of the storage versus biochemical functions of orthophosphate can be elucidated. These insights will be important for incorporating functional components of P and P biogeochemistry into models of ecosystem function, for understanding how P may regulate global change responses.