Subclass:
Dilleniidae
Links to Family Pages:
Subclass consisting of 77 families, and about 25,000 species of angiosperms - the bulk (3/4) of the subclass coming from five orders: Violales, Capparales, Ericales, Theales, and Malvales. They are more advanced than the Magnoliidae by being syncarpous and less advanced than the Asteridae by being largely polypetalous rather than sympetalous or having more than two fused carpels. The Dilleniidae has been distinguished from the Rosidae in that species with numerous stamens have the stamens initiated in centrifugal (rather than centripetal) sequence and commonly exhibiting parietal placentation which is rare in Rosidae.
Molecular phylogenetic studies indicate that the Dilleniidae are not a natural group and should be broken up. Two carnivorous families (Nepenthaceae and Droseraceae) belong to Caryophyllidae. Most of the sympetalous families (e.g., Ericaceae, Monotropaceae, Pyrolaceae, Primulaceae) belong to the largely sympetalous Asteridae. The remainder of the Dilleniidae belong to various and different lineages of the expanded Rosidae.