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Flowering plants are that bear flowers and , and form the clade Angiospermae (), commonly called angiosperms. They include all Forb (flowering plants without a woody stem), and grass-like plants, a vast majority of broad-leaved trees, and , and most Aquatic plant. The term "angiosperm" is derived from the Greek language words ἀγγεῖον /angeion ('container, vessel') and σπέρμα / sperma ('seed'), meaning that the seeds are enclosed within a fruit. They are by far the most diverse group of Embryophyte with 64 orders, 416 families, approximately 13,000 known Genus and 300,000 known species. Angiosperms were formerly called Magnoliophyta ().
Angiosperms are distinguished from the other Spermatophyte plants, the , by having , xylem consisting of instead of tracheids, endosperm within their seeds, and fruits that completely envelop the seeds. The ancestors of flowering plants diverged from the common ancestor of all living gymnosperms before the end of the Carboniferous, over 300 million years ago. In the Cretaceous, angiosperms diversified explosively, becoming the dominant group of plants across the planet.
Agriculture is almost entirely dependent on angiosperms, and a small number of flowering plant families supply nearly all plant-based food and livestock feed. Rice, maize, and wheat provide half of the world's calorie intake, and all three plants are cereals from the Poaceae family (colloquially known as grasses). Other families provide materials such as wood, paper and cotton, and supply numerous ingredients for traditional and modern medicines. Flowering plants are also commonly grown for decorative purposes, with certain flowers playing a significant role in many cultures.
Out of the "Big Five" in Earth's history, only the Cretaceous–Paleogene extinction event had occurred while angiosperms dominated plant life on the planet. Today, the Holocene extinction affects all kingdoms of complex life on Earth, and conservation measures are necessary to protect plants in their habitats in the wild ( in situ), or failing that, ex situ in or artificial habitats like . Otherwise, around 40% of plant species may become Extinction due to human actions such as habitat destruction, introduction of invasive species, unsustainable logging and collection of medicinal plants or . Further, climate change is starting to impact plants and is likely to cause many species to become extinct by 2100.
| '' flower in section. and are replaced here by a fused tube, the corona, and tepals.]] | |
| The gametophytes are smaller than those of gymnosperms. The smaller size of the pollen reduces the time between pollination and fertilization, which in gymnosperms is up to a year. | is a reduced female gametophyte.]] |
| Endosperm forms after fertilization but before the zygote divides. It provides food for the developing embryo, the , and sometimes the seedling. | |
| vessels (long tubes).]] |
The largest angiosperms are Eucalyptus gum trees of Australia, and Shorea faguetiana, dipterocarp rainforest trees of Southeast Asia, both of which can reach almost in height. The smallest are Wolffia duckweeds which float on freshwater, each plant less than across.
Considering their method of obtaining energy, some 99% of flowering plants are photosynthetic , deriving their energy from sunlight and using it to create molecules such as . The remainder are parasitic, whether on fungi like the orchids for part or all of their life-cycle, or Parasitic plant, either wholly like the broomrapes, Orobanche, or partially like the witchweeds, Striga.
In terms of their environment, flowering plants are cosmopolitan, occupying a wide range of on land, in fresh water and in the sea. On land, they are the dominant plant group in every habitat except for frigid moss-lichen tundra and coniferous forest. The in the Alismatales grow in marine environments, spreading with that grow through the mud in sheltered coastal waters. (2023). 9780128237311 ISBN 9780128237311
Some specialised angiosperms are able to flourish in extremely acid or alkaline habitats. The , many of which live in nutrient-poor acid , are carnivorous plants, able to derive nutrients such as nitrate from the bodies of trapped insects. Other flowers such as Gentiana verna, the spring gentian, are adapted to the alkaline conditions found on calcium-rich chalk and limestone, which give rise to often dry Topography such as limestone pavement.
As for their growth habit, the flowering plants range from small, soft , often living as annual plant or biennials that set seed and die after one growing season, to large Perennial plant woody that may live for many centuries and grow to many metres in height. Some species grow tall without being self-supporting like trees by climbing plant on other plants in the manner of or .
The diversity of flowering plants is not evenly distributed. Nearly all species belong to the eudicot (75%), monocot (23%), and magnoliid (2%) clades. The remaining five clades contain a little over 250 species in total; i.e. less than 0.1% of flowering plant diversity, divided among nine families. The 25 most species-rich of 443 families, containing over 166,000 species between them in their APG circumscriptions, are:
| + The 25 largest angiosperm families |
| 22,750 |
| 21,950 |
| 19,400 |
| 13,150 |
| 10,035 |
| 7,175 |
| 5,735 |
| 5,005 |
| 4,625 |
| 4,555 |
| 4,350 |
| 4,225 |
| 4,025 |
| 3,995 |
| 3,870 |
| 3,780 |
| 3,710 |
| 3,600 |
| 3,540 |
| 3,500 |
| 2,830 |
| 2,740 |
| 2,625 |
| 2,525 |
| 2,500 |
Flowers produce two kinds of reproductive cells. , which divide to become pollen, are the male cells; they are borne in the . (1970). 9781349003648, Macmillan Education. ISBN 9781349003648 The female cells, , divide to become the egg cell. They are contained in the ovule and enclosed in the carpel; one or more carpels form the pistil.
The flower may consist only of these parts, as in Anemophily plants like the willow, where each flower comprises only a few or two carpels. In Entomophily or Ornithophily plants, other structures protect the and attract pollinators. The individual members of these surrounding structures are known as and (or in flowers such as Magnolia where sepals and petals are not distinguishable from each other). The outer series (calyx of sepals) is usually green and leaf-like, and functions to protect the rest of the flower, especially the bud. The inner series (corolla of petals) is, in general, white or brightly colored, is more delicate in structure, and attracts pollinators by colour, Floral scent, and nectar.
Most flowers are hermaphrodite, producing both pollen and ovules in the same flower, but some use other devices to reduce self-fertilization. Heteromorphic flowers have carpels and stamens of differing lengths, so animal cannot easily transfer pollen between them. Homomorphic flowers may use a biochemical self-incompatibility to discriminate between self and non-self pollen grains. Dioecious plants such as holly have male and female flowers on separate plants. Monoecious plants have separate male and female flowers on the same plant; these are often wind-pollinated, as in maize, but include some insect-pollinated plants such as Cucurbita squashes.
Other parts of the flower often contribute to forming the fruit. For example, in the apple, the hypanthium forms the edible flesh, surrounding the ovaries which form the tough cases around the seeds.
Apomixis, setting seed without fertilization, is found naturally in about 2.2% of angiosperm genera. Some angiosperms, including many citrus varieties, are able to produce fruits through a type of apomixis called nucellar embryony.
| + Major food-providing families |
| Most feedstocks, inc. rice, maize, wheat, barley, rye, , pearl millet, sugar cane, sorghum |
| , , lentils; for animal feed, clover, alfalfa |
| , , capsicum, |
| Cucurbita, , , |
| Cabbage and its varieties, e.g. Brussels sprout, broccoli; mustard plant; rapeseed |
| Parsnip, carrot, parsley, coriander, fennel, cumin, caraway |
| Oranges, , |
| , , cherry, , , |
Flowering plants provide a diverse range of materials in the form of wood, paper, fibers such as cotton, flax, and hemp, medicinal plants such as digoxin and , and decorative and landscaping plants. Coffee and hot chocolate are beverages from flowering plants.
Conservation in this context is the attempt to prevent extinction, whether in situ by protecting plants and their habitats in the wild, or ex situ in or as living plants. Some 3000 botanic gardens around the world maintain living plants, including over 40% of the species known to be threatened, as an "insurance policy against extinction in the wild." The United Nations' Global Strategy for Plant Conservation asserts that "without plants, there is no life". It aims to "halt the continuing loss of plant diversity" throughout the world.
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