Abstract
Insufficient calcium (Ca) or magnesium (Mg) in the diets of humans and animals has negative effects on health. Knowledge of the concentrations of Ca and Mg in edible crops can help inform the formulation of appropriate diets. There are large differences in shoot concentrations of both Ca ([Ca](shoot)) and Mg([Mg](shoot)) between angiosperm orders. For example, relative to other angiosperms, commelinid monocot species generally have lower [Ca](shoot) and [Mg](shoot); species from the Cucurbitales, Malvales and Brassicales generally have higher [Ca](shoot) and [Mg](shoot); and species from the Oxalidales and Caryophyllales generally have higher [Mg]shoot but similar [Ca](shoot), which results in higher [Mg](shoot)/[Ca]shoot quotients. In this paper the evolution of the combined traits of high [Mg](shoot) and high [Mg](shoot)/[Ca](shoot) quotient in the Caryophyllales was resolved at the family level. All Caryophyllales families had high mean [Mg](shoot) and [Mg](shoot)/[Ca](shoot) quotients, suggesting that both of these traits evolved in an ancient ancestor of all Caryophyllales families.