WordNet (r) 3.0 (2006):

subclass Magnoliidae
    n 1: a group of families of trees and shrubs and herbs having
         well-developed perianths and apocarpous ovaries and
         generally regarded as the most primitive extant flowering
         plants; contains 36 families including Magnoliaceae and
         Ranunculaceae; sometimes classified as a superorder [syn:
         Magnoliidae, subclass Magnoliidae, ranalian complex]