Page "Cornales" Paragraph 9

Molecular data suggest that there are four clades within the Cornales: Cornus-Alangium, nyssoids-mastixioids, Hydrangeaceae-Loasaceae, and Grubbia-Curtisia, with Hydrostachyaceae in an uncertain position, possibly basal.

However, the relationship between these clades is unclear, and as a result of many historical taxonomic interpretations and differing opinions regarding the significance of morphological variations, rankings of taxa within the order are inconsistent.

These difficulties in interpreting the systematics of Cornales may represent an early and rapid diversification of the groups within the order.