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Magnoliophyta(măg'nōlēŏf`ətə), division of the plant kingdom consisting of those organisms commonly called the flowering plants, or angiospermsangiosperm
, term denoting seed plants in which the ovules, or young seeds, are enclosed within the ovary (that part of the pistil specialized for seed production), in contrast to the gymnosperms, in which the seeds are not enclosed within an ovary.
..... Click the link for more information. . The angiosperms have leaves, stems, and roots, and vascular, or conducting, tissue (xylem and phloem). The ovules, which develop into seeds, are enclosed within an ovary, hence the term angiosperm, meaning "enclosed seed." The flowering plants are the source of all agricultural crops, cereal grains and grasses, garden and roadside weeds, familiar broad-leaved shrubs and trees, and most ornamentals.
Class Magnoliopsida (Dicotyledons)
Plants of this class usually have two seed leaves, or cotyledons, and cambium tissue in the stems (see meristemmeristem
, a specialized section of plant tissue characterized by cell division and growth. Much of the mature plant's growth is provided by meristems. Apical meristems found at the tips of stems and roots increase the length of these sections.
..... Click the link for more information. ). Much the larger of the two classes of flowering plants, dicots are divided into many families, among which several of the more conspicuous and easily recognized are the willowwillow,
common name for some members of the Salicaceae, a family of deciduous trees and shrubs of worldwide distribution, especially abundant from north temperate to arctic areas.
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common name for the Ranunculaceae, a family of chiefly annual or perennial herbs of cool regions of the Northern Hemisphere. Thought to be one of the most primitive families of dicotyledenous plants, the Ranunculaceae typically have a simple
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common name for some members of the Caryophyllaceae, a family of small herbs found chiefly in north temperate zones (especially the Mediterranean area) but with several genera indigenous to south temperate zones and high altitudes of tropical mountains.
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common name for the Cruciferae, a large family chiefly of herbs of north temperate regions. The easily distinguished flowers of the Cruciferae have four petals arranged diagonally ("cruciform") and alternating with the four sepals.
..... Click the link for more information. , saxifragesaxifrage
, common name for several members of the Saxifragaceae, a family of widely varying herbs, shrubs, and small trees of cosmopolitan distribution. They are found especially in north temperate zones and include many arctic and alpine species.
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common name for some members of the Rosaceae, a large family of herbs, shrubs, and trees distributed over most of the earth, and for plants of the genus Rosa, the true roses.
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hardy, annual, climbing leguminous plant (Pisum sativum) of the family Leguminosae (pulse family), grown for food by humans at least since the early Bronze Age; no longer known in the wild form.
..... Click the link for more information. , heather (see heathheath,
in botany, common name for some members of the Ericaceae, a family of chiefly evergreen shrubs with berry or capsule fruits. Plants of the heath family form the characteristic vegetation of many regions with acid soils, particularly the moors, swamps, and mountain slopes
..... Click the link for more information. ), gentiangentian
, common name for some members of the Gentianaceae, a family of widely distributed herbs, chiefly perennial and fall blooming. There are many types of gentians (genus Gentiana and similar species of other genera), most of which have blue flowers.
..... Click the link for more information. , bluebellbluebell,
common name for several plants belonging to completely different classes, particularly the bellflower and the Virginia cowslip, or Virginia bluebell, of the family Boraginaceae (borage family) and the wood hyacinth, a squill of the family Liliaceae (lily family).
..... Click the link for more information. , and asteraster
[Gr.,=star], common name for the Asteraceae (Compositae), the aster family, in North America, name for plants of the genus Aster, sometimes called wild asters, and for a related plant more correctly called China aster (Callistephus chinensis
..... Click the link for more information. families.
Class Liliopsida (Monocotyledons)
Plants of this class generally have only one seed leaf, or cotyledon, and generally lack cambium tissue. The most common families are the grassgrass,
any plant of the family Gramineae, an important and widely distributed group of vascular plants, having an extraordinary range of adaptation. Numbering approximately 600 genera and 9,000 species, the grasses form the climax vegetation (see ecology) in great areas of low
..... Click the link for more information. , palmpalm,
common name for members of the Palmae, a large family of chiefly tropical trees, shrubs, and vines. Most species are treelike, characterized by a crown of compound leaves, called fronds, terminating a tall, woody, unbranched stem.
..... Click the link for more information. , arumarum,
common name for the Araceae, a plant family mainly composed of species of herbaceous terrestrial and epiphytic plants found in moist to wet habitats of the tropics and subtropics; some are native to temperate zones.
..... Click the link for more information. , sedgesedge,
common name for members of the Cyperaceae, a family of grasslike and rushlike herbs found in all parts of the world, especially in marshes of subarctic and temperate zones.
..... Click the link for more information. , lilylily,
common name for the Liliaceae, a plant family numbering several thousand species of as many as 300 genera, widely distributed over the earth and particularly abundant in warm temperate and tropical regions.
..... Click the link for more information. , and orchidorchid,
popular name for members of the Orchidaceae, a family of perennial herbs widely distributed in both hemispheres. The unusually large family (of some 450 genera and an estimated 10,000 to 17,500 species) includes terrestrial, epiphytic (see epiphyte), and saprophytic
..... Click the link for more information. families.
A division of seed plants consisting of about 250,000 species, which form the bulk and most conspicuous element of the land plants. Often called flowering plants or angiosperms, they have several unique characteristics, the most prominent of which are their reproductive structure, flowers, and covered seeds. The other obvious woody land plants are the gymnosperms, which have cones instead of flowers and have naked seeds. Another trait distinguishing the angiosperms is the presence of double fertilization, which results in the production of stored food (starch or oils) within their seeds. See Flower
Angiosperms range from some of the smallest plants known to large forest trees, and they occur in all habitats, including the oceans, where they are only a minor element in most marine ecosystems. Some are capable of growing directly on rock surfaces as well as on the limbs of trees. The angiosperms are usually considered to be the most highly evolved division of the subkingdom Embryobionta. Their highly specialized and relatively efficient conducting tissues, combined with the protection of their ovules in an ovary, give them a competitive advantage over most other groups of land plants in most regions. See Embryobionta
The angiosperms may be characterized as vascular plants with roots, stems, and leaves, usually with well-developed vessels in the xylem and with companion cells in the phloem. The central cylinder has leaf gaps or scattered vascular bundles; the ovules are enclosed in an ovary; and the female gametophyte is reduced to a few-nucleate embryo sac without an archegonium. The male gametophyte is reduced to a tiny pollen grain that gives rise to a pollen tube containing a tube nucleus and two sperms; one sperm fuses with the egg in the embryo sac to form a zygote, and the other fuses with two nuclei of the embryo sac to form a triple fusion nucleus that is typically the forerunner of the endosperm of the seed. See Leaf, Phloem, Pollen, Reproduction (plant), Root (botany), Seed, Stem, Xylem
Among plants with alternation of sporophyte and gametophyte generations, the angiosperms represent the most extreme stage in reduction of the gametophyte, which in effect is reduced to a mere stage in the reproduction of the sporophyte. The pollen grain, with its associated pollen tube, and the embryo sac represent the male and female gametophyte generations; the endosperm is a new structure not referable to either generation; and the remainder of the plant throughout its life cycle is the sporophyte. Many angiosperms can also propagate asexually by means of creeping stems or roots or by other specialized vegetative structures such as bulbils.
It is obvious to biologists that the angiosperms must have evolved from gymnosperms, but beyond this the facts are obscure. They appear in the fossil record early in the Cretaceous Period as obvious angiosperms, without any hint of a connection to any particular group of gymnosperms. Many believe that among the gymnosperms the seed ferns provide the most likely ancestors. See Paleobotany, Pinophyta
The Magnoliophyta consist of two large groups that have not been formally named: the eudicots and the magnoliids. The eudicots are characterized by flowers that are highly organized in terms of the number and orientation of parts whereas the magnoliids have many parts without any particular fixed patterns among the parts—except for the monocots, in which the most developed groups, like the eudicots, exhibit developed flowers with highly organized patterns. See Liliopsida, Magnoliopsida