The betalain pigments are unique in plants of this order and occur in all its core families with the exception of Caryophyllaceae and Molluginaceae.
According to molecular clock calculations, the lineage that led to Caryophyllales split from other plants about 111 million years ago.
[9] The possible connection between sympetalous angiosperms and Caryophyllales was presaged by Bessey, Hutchinson, and others; as Lawrence relates: "The evidence is reasonably conclusive that the Primulaceae and the Caryophyllaceae have fundamentally the same type of gynecia, and as concluded by Douglas (1936)(and essentially Dickson, 1936) '...the vascular pattern and the presence of locules at the base of the ovary point to the fact that the present much reduced flower of the Primulaceae has descended from an ancestor which was characterized by a plurilocular ovary and axial placentation.
[1] As circumscribed by the APG II system (2003), this order includes well-known plants like cacti, carnations, spinach, beet, rhubarb, sundews, venus fly traps, and bougainvillea.
Recent molecular and biochemical evidence has resolved additional well-supported clades within the Caryophyllales.