Eudicotyledons

One of the two major types of flowering plants (angiosperms), characterized by possession of three apertures in their pollen; the other major type is magnoliids. Although this difference in pollen development and form has been known for a long time, it has become clear, as a result of several studies of deoxyribonucleic acid (DNA) sequences, that this difference is very significant. The high degree of coincidence of the genetic data with this pollen distinction means that it is more important to recognize this distinction than the number of seed leaves, as previously thought. See also Dicotyledons; Flower; Magnoliales; Monocotyledons.