The angiosperms or flowering plants are by far the most important and best known group of plants. They appeared and rose to importance during the later Cretaceous period. By the early Tertiary angiosperms had spread worldwide and become the dominant form of land plant, supplanting the Coniferales and other gymnosperms.
The angiosperms include all living flowering plants and have traditionally been divided into the dicotyledons and the monocotyledons according to the structure of their seeds. It is now known that this is something of an artificial grouping.