In the classification system of
Dahlgren the Cornales were in the
superorder Corniflorae (also called Cornanae). Under the
APG IV system, the Cornales order includes these families: •
Cornaceae (the
dogwood family) •
Curtisiaceae (cape lancewood) •
Grubbiaceae (the
sillyberry family) •
Hydrangeaceae (the
hydrangea family) •
Hydrostachyaceae •
Loasaceae (the
stickleaf family) •
Nyssaceae, (the
tupelos) The oldest fossils assigned with confidence to the order are
Hironoia fusiformis, described from
Coniacian age Japanese coalified fruits, and
Suciacarpa starrii described from American
permineralized fruits of
Campanian age.
Phylogeny The Cornales order is sister to the remainder of the large and diverse
asterid clade. The Cornales are highly geographically
disjunct and
morphologically diverse, which has led to considerable confusion regarding the proper circumscription of the groups within the order and the relationships between them. Under the
Cronquist system, the order comprised the families Cornaceae, Nyssaceae,
Garryaceae, and
Alangiaceae, and was placed among the
Rosidae, but this interpretation is no longer followed. Many families and genera previously associated with the Cornales have been removed, including Garryaceae,
Griselinia,
Corokia, and
Kaliphora, among others. }} Molecular data suggest four clades are within the Cornales:
Cornus-Alangium,
nyssoids-mastixioids, Hydrangeaceae-Loasaceae, and
Grubbia-Curtisia, with the 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. ==References==