Wheat is a grass cultivated for its seed, a cereal grain, a worldwide staple food. The many species of wheat together make up the genus Triticum; the archaeological record suggests that wheat was first cultivated in the regions of the Fertile Crescent around 9600 BCE. Botanically, the wheat kernel is a type of fruit called a caryopsis. Wheat is grown on more land area than any other food crop. World trade in wheat is greater than for all other crops combined. In 2016, world production of wheat was 749 million tonnes, making it the second most-produced cereal after maize. Since 1960, world production of wheat and other grain crops has tripled and is expected to grow further through the middle of the 21st century. Global demand for wheat is increasing due to the unique viscoelastic and adhesive properties of gluten proteins, which facilitate the production of processed foods, whose consumption is increasing as a result of the worldwide industrialization process and the westernization of the diet.
Wheat is an important source of carbohydrates. Globally, it is the leading source of vegetal protein in human food, having a protein content of about 13%, high compared to other major cereals but low in protein quality for supplying essential amino acids; when eaten as the whole grain, wheat is a source of dietary fiber. In a small part of the general population, gluten – the major part of wheat protein – can trigger coeliac disease, noncoeliac gluten sensitivity, gluten ataxia, dermatitis herpetiformis. Cultivation and repeated harvesting and sowing of the grains of wild grasses led to the creation of domestic strains, as mutant forms of wheat were preferentially chosen by farmers. In domesticated wheat, grains are larger, the seeds remain attached to the ear by a toughened rachis during harvesting. In wild strains, a more fragile rachis allows the ear to shatter and disperse the spikelets. Selection for these traits by farmers might not have been deliberately intended, but have occurred because these traits made gathering the seeds easier.
As the traits that improve wheat as a food source involve the loss of the plant's natural seed dispersal mechanisms domesticated strains of wheat cannot survive in the wild. Cultivation of wheat began to spread beyond the Fertile Crescent after about 8000 BCE. Jared Diamond traces the spread of cultivated emmer wheat starting in the Fertile Crescent sometime before 8800 BCE. Archaeological analysis of wild emmer indicates that it was first cultivated in the southern Levant, with finds dating back as far as 9600 BCE. Genetic analysis of wild einkorn wheat suggests that it was first grown in the Karacadag Mountains in southeastern Turkey. Dated archeological remains of einkorn wheat in settlement sites near this region, including those at Abu Hureyra in Syria, suggest the domestication of einkorn near the Karacadag Mountain Range. With the anomalous exception of two grains from Iraq ed-Dubb, the earliest carbon-14 date for einkorn wheat remains at Abu Hureyra is 7800 to 7500 years BCE. Remains of harvested emmer from several sites near the Karacadag Range have been dated to between 8600 and 8400 BCE, that is, in the Neolithic period.
With the exception of Iraq ed-Dubb, the earliest carbon-14 dated remains of domesticated emmer wheat were found in the earliest levels of Tell Aswad, in the Damascus basin, near Mount Hermon in Syria. These remains were dated by Willem van Zeist and his assistant Johanna Bakker-Heeres to 8800 BCE, they concluded that the settlers of Tell Aswad did not develop this form of emmer themselves, but brought the domesticated grains with them from an as yet unidentified location elsewhere. The cultivation of emmer reached Greece and Indian subcontinent by 6500 BCE, Egypt shortly after 6000 BCE, Germany and Spain by 5000 BCE. "The early Egyptians were developers of bread and the use of the oven and developed baking into one of the first large-scale food production industries." By 3000 BCE, wheat had reached Scandinavia. A millennium it reached China; the oldest evidence for hexaploid wheat has been confirmed through DNA analysis of wheat seeds, dating to around 6400-6200 BCE, recovered from Çatalhöyük.
The first identifiable bread wheat with sufficient gluten for yeasted breads has been identified using DNA analysis in samples from a granary dating to 1350 BCE at Assiros in Macedonia. From Asia, wheat continued to spread across Europe. In the British Isles, wheat straw was used for roofing in the Bronze Age, was in common use until the late 19th century. Technological advances in soil preparation and seed placement at planting time, use of crop rotation and fertilizers to improve plant growth, advances in harvesting methods have all combined to promote wheat as a viable crop; when the use of seed drills replaced broadcasting sowing of seed in the 18th century, another great increase in productivity occurred. Yields of pure wheat per unit area increased as methods of crop rotation were applied to long cultivated land, the use of fertilizers became widespread. Improved agricultural husbandry has more included threshing machines and reaping machines, tractor-drawn cultivators and planters, better varieties.
Great expansion of wheat production occurred as new arable land was farmed in the Americas and Australia in the 19th and 20th centuries. Leaves emerge from the shoot apical meristem in a telescoping fashion until the transition to reprod
Nymphaeaceae is a family of flowering plants called water lilies. They live as rhizomatous aquatic herbs in tropical climates around the world; the family contains five genera with about 70 known species. Water lilies are rooted in soil in bodies of water, with leaves and flowers floating on or emergent from the surface; the leaves are round, with a radial notch in Nymphaea and Nuphar, but circular in Victoria and Euryale. Water lilies are a well studied clade of plants because their large flowers with multiple unspecialized parts were considered to represent the floral pattern of the earliest flowering plants, genetic studies confirmed their evolutionary position as basal angiosperms. Analyses of floral morphology and molecular characteristics and comparisons with a sister taxon, the family Cabombaceae, however, that the flowers of extant water lilies with the most floral parts are more derived than the genera with fewer floral parts. Genera with more floral parts, Nymphaea, have a beetle pollination syndrome, while genera with fewer parts are pollinated by flies or bees, or are self- or wind-pollinated.
Thus, the large number of unspecialized floral organs in the Nymphaeaceae is not an ancestral condition for the clade. Water lilies do not have surface leaves during winter, therefore the gases in the rhizome lacunae access equilibrium with the gases of the sediment water; the leftover of internal pressure is embodied by the constant streams of bubbles that outbreak when rising leaves are ruptured in the spring. The Nymphaeaceae are aquatic, rhizomatous herbs; the family is further characterized by scattered vascular bundles in the stems, frequent presence of latex with distinct, stellate-branched sclereids projecting into the air canals. Hairs are simple producing mucilage. Leaves are alternate and spiral, opposite or whorled, peltate or nearly so, entire to toothed or dissected, short to long petiolate), with blade submerged, floating or emergent, with palmate to pinnate venation. Stipules are either absent. Flowers are solitary, radial, with a long pedicel and floating or raised above the surface of the water, with girdling vascular bundles in receptacle.
Female and male parts of the flower are active at different times to facilitate cross-pollination. Sepals are 4-12, distinct to connate and petal-like. Petals lacking or 8 to numerous, inconspicuous to showy intergrading with stamens. Stamens are 3 to numerous, the innermost sometimes represented by staminodes. Filaments are distinct, free or adnate to petaloid staminodes and well differentiated from anthers to laminar and poorly differentiated from anthers. Carpels are 3 to numerous, connate. Fruit is an aggregate of a berry, or an irregularly dehiscent fleshy spongy capsule. Seeds are arillate, more or less lacking sperm. Nymphaeaceae has been investigated systematically for decades because botanists considered their floral morphology to represent one of the earliest groups of angiosperms. Modern genetic analyses by the Angiosperm Phylogeny Group researchers has confirmed its basal position among flowering plants. In addition, the Nymphaeaceae are more genetically diverse and geographically dispersed than other basal angiosperms.
Nymphaeaceae is placed in the order Nymphaeales, the second diverging group of angiosperms after Amborella in the most accepted flowering plant classification system, APG IV system. Nymphaeaceae is a small family of three to six genera: Barclaya, Nuphar, Nymphaea and Victoria; the genus Barclaya is sometimes given rank as its own family, Barclayaceae, on the basis of an extended perianth tube arising from the top of the ovary and by stamens that are joined in the base. However, molecular phylogenetic work includes it in Nymphaeaceae; the genus Ondinea has been shown to be a morphologically aberrant species of Nymphaea, is now included in this genus. The genera Euryale, of far east Asia, Victoria, from South America, are related despite their geographic distance, but their relationship toward Nymphaea need further studies; the sacred lotus was once thought to be a water lily, but is now recognized to be a modified eudicot in its own family Nelumbonaceae of the order Proteales. The beautiful nature of water lilies has led to their widespread use as ornamental plants.
The Mexican water lily, native to the Gulf Coast of North America, is planted throughout the continent. It has escaped from cultivation and become invasive in some areas, such as California's San Joaquin Valley, it is difficult to eradicate. Populations can be controlled by cutting top growth. Herbicides can be used to control populations using glyphosate and fluridone; the white water lily is the national flower of Bangladesh and state flower for Andhra Pradesh, India. The seal of Bangladesh contains a lily floating on water; the blue waterlily is the national flower of Sri Lanka. It is the birth flower for July. Lily pads known as Seeblätter, are a charge in Northern European heraldry coloured red, appear on the flag of Friesland and the coat of arms of Denmark; the water lily has a special place in Sangam literature and Tamil poetics, where it is considered symbolic of the grief of separation. Water lilies were depicted by the French artist Claude Monet in a series of paintings. Nelumbo Pamplemousses Botanical Garden, famous for its giant w
A flower garden or floral garden is any garden where flowers are grown and displayed. Because flowers bloom at varying times of the year, some plants are annual, dying each winter, the design of flower gardens can take into consideration maintaining a sequence of bloom and consistent color combinations through varying seasons. Besides organizing the flowers in bedding-out schemes limited to annual and perennial flower beds, careful design takes the labour time, the color pattern of the flowers into account; the labour time can be decreased by using techniques such as mulching. In flower meadows, grass growth can be moderated by planting parasitic plants such as Rhinanthus. Flower color is another important feature of both the herbaceous border and the mixed border that includes shrubs as well as herbaceous plants. Flower gardens are sometimes tied in function to other kinds of gardens, like knot gardens or herb gardens, many herbs having decorative function, some decorative flowers being edible.
A simpler alternative to the designed flower garden is the "wildflower" seed mix, with assortments of seeds which will create a bed that contains flowers of various blooming seasons, so that some portion of them should always be in bloom. The best mixtures include combinations of perennial and biennials, which may not bloom until the following year, annuals that are "self-seeding", so they will return, creating a permanent flowerbed. Another more recent trend is the "flower garden in a box", where the entire design of a flower garden is pre-packaged, with separate packets of each kind of flower, a careful layout to be followed to create the proposed pattern of color in the garden-to-be. Many, if not most, plants considered decorative flowers originated as weeds, which if attractive enough would sometimes be tolerated by farmers because of their appeal; this led to an artificial selection process. This is thought to have occurred for the entire history of agriculture even earlier, when people tended to favor occurring food-gathering spots.
This may explain why many flowers function as companion plants to more useful agricultural plants. Once domesticated, most flowers were grown either separately or as part of gardens having some other primary function. In the West, the idea of gardens dedicated to flowers did not become common until the 19th century, though in fact many modern gardens are indeed flower gardens. Flower gardens are, indeed, a key factor in modern landscape design and architecture for large businesses, some of which pay to have large flower gardens torn out and replaced each season, in order to keep the color patterns consistent. A functional garden used to grow flowers for indoor use rather than outdoor display is known as a cutting garden, it is only a feature of large residences. The cutting garden is placed in a fertile and sunlight position out of public view and is not artistically arranged, as it contains flowers for cutting; the cutting garden may comprise a herb garden and ornamental vegetables as well. Raised-bed gardening Bedding Herbaceous border National Garden Bureau National Gardening Association Winnipeg In Bloom Documentary produced by Prairie Public Television
Viola is a genus of flowering plants in the violet family Violaceae. It is the largest genus in the family, containing between 600 species. Most species are found in the temperate Northern Hemisphere; some Viola species are perennial plants, some are annual plants, a few are small shrubs. A large number of species and cultivars are grown in gardens for their ornamental flowers. In horticulture the term pansy is used for those multi-colored, large-flowered cultivars which are raised annually or biennially from seed and used extensively in bedding; the terms viola and violet are reserved for small-flowered annuals or perennials, including the wild species. Viola have heart-shaped, scalloped leaves, though a number have palmate leaves or other shapes; the vast majority of Viola species are herbaceous, a substantial number are acaulescent in habit - meaning they lack any noticeable stems and the foliage and flowers appear to rise from the ground. The simple leaves of plants with either habit are arranged alternately.
Plants always have leaves with stipules that are leaf-like. The flowers of the vast majority of the species are zygomorphic with bilateral symmetry; the flowers are formed from five petals. The shape of the petals and placement defines many species, for example, some species have a "spur" on the end of each petal while most have a spur on the lower petal. Solitary flowers end long stalks with a pair of bracteoles; the flowers have five sepals that persist after blooming, in some species the sepals enlarge after blooming. The flowers have five free stamens with short filaments that are oppressed against the ovary, only the lower two stamens have nectary spurs that are inserted on the lowest petal into the spur or a pouch; the flower styles are thickened near the top and the stigmas are head-like, narrowed or beaked. The flowers have a superior ovary with one cell. Viola are most spring blooming with chasmogamous flowers with well-developed petals pollinated by insects. Many species produce self-pollinated cleistogamous flowers in summer and autumn that do not open and lack petals.
In some species the showy chasmogamous flowers are infertile. After flowering, fruit capsules are produced. On drying, the capsules may eject seeds with considerable force to distances of several meters; the nutlike seeds have straight embryos, flat cotyledons, soft fleshy endosperm, oily. The seeds of some species are dispersed by ants. Flower colors vary in the genus, ranging from violet, through various shades of blue, yellow and cream, whilst some types are bicolored blue and yellow. Flowering is profuse, may last for much of the spring and summer. One quirk of some Viola is the elusive scent of their flowers. See List of Viola species for a more complete list. Note: Neither Saintpaulia nor Erythronium dens-canis are related to the true Viola; the genus includes dog violets, a group of scentless species which are the most common Viola in many areas, sweet violet, many other species whose common name includes the word "violet". Several species are known as pansies, including the yellow pansy of the Pacific coast.
Common blue violet Viola sororia is the state flower of Wisconsin, Rhode Island and New Jersey. Australia is home to a number of Viola species, including Viola hederacea, Viola betonicifolia and Viola banksii, first collected by Joseph Banks and Daniel Solander on the Cook voyage to Botany Bay. One fossil seed of †Viola rimosa has been extracted from borehole samples of the Middle Miocene fresh water deposits in Nowy Sacz Basin, West Carpathians, Poland. Cultivars of Viola cornuta, Viola cucullata, Viola odorata, are grown from seed. Other species grown include Viola labradorica, Viola pedata, Viola rotundifolia; the modern garden pansy is a plant of complex hybrid origin involving at least three species, V. tricolor, V. altaica, V. lutea. The hybrid horned pansy originates from hybridization involving Viola cornuta. In 2005 in the United States, Viola cultivars were one of the top three bedding plant crops and 111 million dollars worth of flats of Viola were produced for the bedding flower market.
Pansies and violas used for bedding are raised from seed, F1 hybrid seed strains have been developed which produce compact plants of reasonably consistent flower coloring and appearance. Bedding plants are discarded after one growing season. There are hundreds of perennial violetta cultivars. Violettas can be distinguished from violas by the lack of ray markings on their petals; the following cultivars, of mixed or uncertain parentage, have gained the Royal Horticultural Society's Award of Garden Merit:-'Aspasia"Clementina"Huntercombe Purple"Moonlight
A wildflower is a flower that grows in the wild, meaning it was not intentionally seeded or planted. Yet "wildflower" meadows of a few mixed species are sold in seed packets; the term implies that the plant is neither a hybrid nor a selected cultivar, in any way different from the way it appears in the wild as a native plant if it is growing where it would not naturally. The term can refer to the flowering plant as a whole when not in bloom, not just the flower."Wildflower" is not an exact term. Terms like native species, exotic or, introduced species, of which some are labelled invasive species and naturalized are much more accurate. In the United Kingdom, the organisation Plantlife International instituted the "County Flowers scheme" in 2002, for which members of the public nominated and voted for a wild flower emblem for their county; the aim was to spread awareness of the heritage of native species and about the need for conservation, as some of these species are endangered. For example, Somerset has adopted the Cheddar Pink, London the Rosebay Willowherb and Denbighshire/Sir Ddinbych in Wales the rare Limestone Woundwort.
Adonis aestivalis - summer pheasant's-eye Anthemis arvensis Anagallis Agrostemma githago Centaurea cyanus Coreopsis tinctoria Dianthus barbatus Digitalis purpurea Eschscholzia californica - California Poppy Gypsophila elegans Glebionis segetum Lantana spp. Papaver rhoeas Silene latifolia Viola tricolor Dimorphotheca aurantiaca Alnus glutinosa Callirhoe involucrata Potentilla sterilis Prunus padus Petasites hybridus Ranunculus ficaria Tussilago farfara Viola riviniana Phlox drummondii Ulmus sp. List of San Francisco Bay Area wildflowers Superbloom Megaherbs Native plant Naturalisation Media related to Wild flowers at Wikimedia Commons Wildflower Magazine promotes the use and conservation of wildflowers and native plants, Lady Bird Johnson Wildflower Center. Published by the North American Native Plant Society Plantlife, UK organisation Wildflower in Cyprus Information on 1250 native plant species to North Cyprus. Ontario Wildflowers Detailed information about wildflowers of Ontario and Northeastern North America Western USA wildflower reports NPIN: Native Plant Database Native Plant Database from the North American Native Plant Society
Plants are multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. Plants were treated as one of two kingdoms including all living things that were not animals, all algae and fungi were treated as plants. However, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes. By one definition, plants form the clade Viridiplantae, a group that includes the flowering plants and other gymnosperms and their allies, liverworts and the green algae, but excludes the red and brown algae. Green plants obtain most of their energy from sunlight via photosynthesis by primary chloroplasts that are derived from endosymbiosis with cyanobacteria, their chloroplasts contain b, which gives them their green color. Some plants are parasitic or mycotrophic and have lost the ability to produce normal amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although asexual reproduction is common.
There are about 320 thousand species of plants, of which the great majority, some 260–290 thousand, are seed plants. Green plants provide a substantial proportion of the world's molecular oxygen and are the basis of most of Earth's ecosystems on land. Plants that produce grain and vegetables form humankind's basic foods, have been domesticated for millennia. Plants have many cultural and other uses, as ornaments, building materials, writing material and, in great variety, they have been the source of medicines and psychoactive drugs; the scientific study of plants is known as a branch of biology. All living things were traditionally placed into one of two groups and animals; this classification may date from Aristotle, who made the distincton between plants, which do not move, animals, which are mobile to catch their food. Much when Linnaeus created the basis of the modern system of scientific classification, these two groups became the kingdoms Vegetabilia and Animalia. Since it has become clear that the plant kingdom as defined included several unrelated groups, the fungi and several groups of algae were removed to new kingdoms.
However, these organisms are still considered plants in popular contexts. The term "plant" implies the possession of the following traits multicellularity, possession of cell walls containing cellulose and the ability to carry out photosynthesis with primary chloroplasts; when the name Plantae or plant is applied to a specific group of organisms or taxon, it refers to one of four concepts. From least to most inclusive, these four groupings are: Another way of looking at the relationships between the different groups that have been called "plants" is through a cladogram, which shows their evolutionary relationships; these are not yet settled, but one accepted relationship between the three groups described above is shown below. Those which have been called "plants" are in bold; the way in which the groups of green algae are combined and named varies between authors. Algae comprise several different groups of organisms which produce food by photosynthesis and thus have traditionally been included in the plant kingdom.
The seaweeds range from large multicellular algae to single-celled organisms and are classified into three groups, the green algae, red algae and brown algae. There is good evidence that the brown algae evolved independently from the others, from non-photosynthetic ancestors that formed endosymbiotic relationships with red algae rather than from cyanobacteria, they are no longer classified as plants as defined here; the Viridiplantae, the green plants – green algae and land plants – form a clade, a group consisting of all the descendants of a common ancestor. With a few exceptions, the green plants have the following features in common, they undergo closed mitosis without centrioles, have mitochondria with flat cristae. The chloroplasts of green plants are surrounded by two membranes, suggesting they originated directly from endosymbiotic cyanobacteria. Two additional groups, the Rhodophyta and Glaucophyta have primary chloroplasts that appear to be derived directly from endosymbiotic cyanobacteria, although they differ from Viridiplantae in the pigments which are used in photosynthesis and so are different in colour.
These groups differ from green plants in that the storage polysaccharide is floridean starch and is stored in the cytoplasm rather than in the plastids. They appear to have had a common origin with Viridiplantae and the three groups form the clade Archaeplastida, whose name implies that their chloroplasts were derived from a single ancient endosymbiotic event; this is the broadest modern definition of the term'plant'. In contrast, most other algae not only have different pigments but have chloroplasts with three or four surrounding membranes, they are not close relatives of the Archaeplastida having acquired chloroplasts separately from ingested or symbiotic green and red algae. They are thus not included in the broadest modern definition of the plant kingdom, although they were in the past; the green plants or Viridiplantae were traditionally divided into the green algae (including
In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a woody trunk and branches as a way to tower above other plants to compete for sunlight. Trees tend to be long-lived, some reaching several thousand years old. In wider definitions, the taller palms, tree ferns and bamboos are trees. Trees have been in existence for 370 million years, it is estimated. A tree has many secondary branches supported clear of the ground by the trunk; this trunk contains woody tissue for strength, vascular tissue to carry materials from one part of the tree to another. For most trees it is surrounded by a layer of bark. Below the ground, the roots spread out widely. Above ground, the branches divide into smaller shoots.
The shoots bear leaves, which capture light energy and convert it into sugars by photosynthesis, providing the food for the tree's growth and development. Trees reproduce using seeds. Flowers and fruit may be present, but some trees, such as conifers, instead have pollen cones and seed cones. Palms and bamboos produce seeds, but tree ferns produce spores instead. Trees play a significant role in moderating the climate, they remove carbon dioxide from the atmosphere and store large quantities of carbon in their tissues. Trees and forests provide a habitat for many species of plants. Tropical rainforests are among the most biodiverse habitats in the world. Trees provide shade and shelter, timber for construction, fuel for cooking and heating, fruit for food as well as having many other uses. In parts of the world, forests are shrinking as trees are cleared to increase the amount of land available for agriculture; because of their longevity and usefulness, trees have always been revered, with sacred groves in various cultures, they play a role in many of the world's mythologies.
Although "tree" is a term of common parlance, there is no universally recognised precise definition of what a tree is, either botanically or in common language. In its broadest sense, a tree is any plant with the general form of an elongated stem, or trunk, which supports the photosynthetic leaves or branches at some distance above the ground. Trees are typically defined by height, with smaller plants from 0.5 to 10 m being called shrubs, so the minimum height of a tree is only loosely defined. Large herbaceous plants such as papaya and bananas are trees in this broad sense. A applied narrower definition is that a tree has a woody trunk formed by secondary growth, meaning that the trunk thickens each year by growing outwards, in addition to the primary upwards growth from the growing tip. Under such a definition, herbaceous plants such as palms and papayas are not considered trees regardless of their height, growth form or stem girth. Certain monocots may be considered trees under a looser definition.
Aside from structural definitions, trees are defined by use. The tree growth habit is an evolutionary adaptation found in different groups of plants: by growing taller, trees are able to compete better for sunlight. Trees tend some reaching several thousand years old. Several trees are among the oldest organisms now living. Trees have modified structures such as thicker stems composed of specialised cells that add structural strength and durability, allowing them to grow taller than many other plants and to spread out their foliage, they differ from shrubs, which have a similar growth form, by growing larger and having a single main stem. The tree form has evolved separately in unrelated classes of plants in response to similar environmental challenges, making it a classic example of parallel evolution. With an estimated 60,000-100,000 species, the number of trees worldwide might total twenty-five per cent of all living plant species; the greatest number of these grow in tropical regions and many of these areas have not yet been surveyed by botanists, making tree diversity and ranges poorly known.
The majority of tree species are angiosperms. There are about 1000 species of gymnosperm trees, including conifers, cycads and gnetales. Most angiosperm trees are eudicots, the "true dicotyledons", so named because the seeds contain two cotyledons or seed leaves. There are some trees among the old lineages of flowering plants called basal angiosperms or paleodicots. Wood gives structural strength to the trunk of most types of tree; the vascular system of trees allows water and other chemicals to be di