Sieve-tube plastids

Turner speculated that the two families arose from a common ancestor that likely occupied xeric or halophytic habitats in Gondwana in an area that encompassed what were to become southwestern Africa and southeastern South America. The ancestral types do not still exist, but both families share the unusual, betanidin-based floral chemistry, and the equally unique sieve-tube plastids seen in Caryophyllales but are absent elsewhere in the plant kingdom (Behnke and Turner, 1971). 

Behnke, H.-D. and Turner, B. L. 1971. On specific sieve-tube plastids in CaryophyUales. Taxon 20 731-737. 

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