| angiosperm (ān'jē-ə-spûrm') Any of a large group of plants that produce flowers. They develop seeds from ovules contained in ovaries, and the seeds are enclosed by fruits which develop from carpels. They are also distinguished by the process of double fertilization. The majority of angiosperms belong to two large classes: monocotyledons and eudicotyledons. The angiosperms are the largest phylum of living plants, existing in some 235,000 species. They range from small floating plants only one millimeter (0.04 inch) in length to towering trees that are over 100 meters (328 ft) tall. Compare gymnosperm. |
any member of the more than 300,000 species of flowering plants (division Anthophyta), the largest and most diverse group within the kingdom Plantae. Angiosperms represent approximately 80 percent of all the known green plants now living. The angiosperms are vascular seed plants in which the ovule (egg) is fertilized and develops into a seed in an enclosed hollow ovary. The ovary itself is usually enclosed in a flower, that part of the angiospermous plant that contains the male or female reproductive organs or both. Fruits are derived from the maturing floral organs of the angiospermous plant and are therefore characteristic of angiosperms. By contrast, in gymnosperms (e.g., conifers), the other large group of vascular seed plants, the seeds do not develop enclosed within an ovary but are usually borne exposed on the surfaces of reproductive structures, such as cones, that originally produced the spores.