Caryophyllales are one of the few orders of flowering plants in which the size and delimitation are undisputed. However, their derivation from other taxa and the evolution of families within this group are unsettled. New results in molecular genetics, phytochemistry, ultrastructure and morphology are discussed in this study in relation to both the classical and molecular systematics of the order. In addition, characters like betalains and sieve-element plastids, that have played a major role in shaping the size of the caryophyllales, as well as DNA-data and flower morphology, are critically evaluated with respect to the evolution of the order. (source: Nielsen Book Data)