The flowering plants known as angiosperms, Angiospermae or Magnoliophyta, are the most diverse group of land plants, with 64 orders, 416 families 13,164 known genera and c. 369,000 known species. Like gymnosperms, angiosperms are seed-producing plants. However, they are distinguished from gymnosperms by characteristics including flowers, endosperm within the seeds, the production of fruits that contain the seeds. Etymologically, angiosperm means a plant; the term comes from the Greek words sperma. The ancestors of flowering plants diverged from gymnosperms in the Triassic Period, 245 to 202 million years ago, the first flowering plants are known from 160 mya, they diversified extensively during the Early Cretaceous, became widespread by 120 mya, replaced conifers as the dominant trees from 100 to 60 mya. Angiosperms differ from other seed plants in several ways, described in the table below; these distinguishing characteristics taken together have made the angiosperms the most diverse and numerous land plants and the most commercially important group to humans.
Angiosperm stems are made up of seven layers. The amount and complexity of tissue-formation in flowering plants exceeds that of gymnosperms; the vascular bundles of the stem are arranged such that the phloem form concentric rings. In the dicotyledons, the bundles in the young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium. By the formation of a layer of cambium between the bundles, a complete ring is formed, a regular periodical increase in thickness results from the development of xylem on the inside and phloem on the outside; the soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Owing to differences in the character of the elements produced at the beginning and end of the season, the wood is marked out in transverse section into concentric rings, one for each season of growth, called annual rings.
Among the monocotyledons, the bundles are more numerous in the young stem and are scattered through the ground tissue. They once formed the stem increases in diameter only in exceptional cases; the characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, provide the most trustworthy external characteristics for establishing relationships among angiosperm species; the function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally from the axil of a leaf; as in violets, a flower arises singly in the axil of an ordinary foliage-leaf. More the flower-bearing portion of the plant is distinguished from the foliage-bearing or vegetative portion, forms a more or less elaborate branch-system called an inflorescence. There are two kinds of reproductive cells produced by flowers. Microspores, which will divide to become pollen grains, are the "male" cells and are borne in the stamens.
The "female" cells called megaspores, which will divide to become the egg cell, are contained in the ovule and enclosed in the carpel. The flower may consist only of these parts, as in willow, where each flower comprises only a few stamens or two carpels. Other structures are present and serve to protect the sporophylls and to form an envelope attractive to pollinators; the individual members of these surrounding structures are known as petals. The outer series is green and leaf-like, functions to protect the rest of the flower the bud; the inner series is, in general, white or brightly colored, is more delicate in structure. It functions to attract bird pollinators. Attraction is effected by color and nectar, which may be secreted in some part of the flower; the characteristics that attract pollinators account for the popularity of flowers and flowering plants among humans. While the majority of flowers are perfect or hermaphrodite, flowering plants have developed numerous morphological and physiological mechanisms to reduce or prevent self-fertilization.
Heteromorphic flowers have short carpels and long stamens, or vice versa, so animal pollinators cannot transfer pollen to the pistil. Homomorphic flowers may employ a biochemical mechanism called self-incompatibility to discriminate between self and non-self pollen grains. In other species, the male and female parts are morphologically separated, developing on different flowers; the botanical term "Angiosperm", from the Ancient Greek αγγείον, angeíon and σπέρμα, was coined in the form Angiospermae by Paul Hermann in 1690, as the name of one of his primary divisions of the plant kingdom. This included flowering plants possessing seeds enclosed in capsules, distinguished from his Gymnospermae, or flowering plants with achenial or schizo-carpic fruits, the whole fruit or each of its pieces being here regarded as a seed and naked; the term and its antonym were maintained by Carl Linnaeus with the same sense, but with restricted application, in the names of the orders of his class Didynamia. Its use with any
A seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm plants. Seeds are the product of the ripened ovule, after fertilization by pollen and some growth within the mother plant; the embryo is developed from the seed coat from the integuments of the ovule. Seeds have been an important development in the reproduction and success of gymnosperm and angiosperm plants, relative to more primitive plants such as ferns and liverworts, which do not have seeds and use water-dependent means to propagate themselves. Seed plants now dominate biological niches on land, from forests to grasslands both in hot and cold climates; the term "seed" has a general meaning that antedates the above – anything that can be sown, e.g. "seed" potatoes, "seeds" of corn or sunflower "seeds". In the case of sunflower and corn "seeds", what is sown is the seed enclosed in a shell or husk, whereas the potato is a tuber.
Many structures referred to as "seeds" are dry fruits. Plants producing berries are called baccate. Sunflower seeds are sometimes sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Different groups of plants have other modifications, the so-called stone fruits have a hardened fruit layer fused to and surrounding the actual seed. Nuts are the one-seeded, hard-shelled fruit of some plants with an indehiscent seed, such as an acorn or hazelnut. Seeds are produced in several related groups of plants, their manner of production distinguishes the angiosperms from the gymnosperms. Angiosperm seeds are produced in a hard or fleshy structure called a fruit that encloses the seeds for protection in order to secure healthy growth; some fruits have layers of both fleshy material. In gymnosperms, no special structure develops to enclose the seeds, which begin their development "naked" on the bracts of cones. However, the seeds do become covered by the cone scales.
Seed production in natural plant populations varies from year to year in response to weather variables and diseases, internal cycles within the plants themselves. Over a 20-year period, for example, forests composed of loblolly pine and shortleaf pine produced from 0 to nearly 5 million sound pine seeds per hectare. Over this period, there were six bumper, five poor, nine good seed crops, when evaluated for production of adequate seedlings for natural forest reproduction. Angiosperm seeds consist of three genetically distinct constituents: the embryo formed from the zygote, the endosperm, triploid, the seed coat from tissue derived from the maternal tissue of the ovule. In angiosperms, the process of seed development begins with double fertilization, which involves the fusion of two male gametes with the egg cell and the central cell to form the primary endosperm and the zygote. Right after fertilization, the zygote is inactive, but the primary endosperm divides to form the endosperm tissue.
This tissue becomes the food the young plant will consume until the roots have developed after germination. After fertilization the ovules develop into the seeds; the ovule consists of a number of components: The funicle or seed stalk which attaches the ovule to the placenta and hence ovary or fruit wall, at the pericarp. The nucellus, the remnant of the megasporangium and main region of the ovule where the megagametophyte develops; the micropyle, a small pore or opening in the apex of the integument of the ovule where the pollen tube enters during the process of fertilization. The chalaza, the base of the ovule opposite the micropyle, where integument and nucellus are joined together; the shape of the ovules as they develop affects the final shape of the seeds. Plants produce ovules of four shapes: the most common shape is called anatropous, with a curved shape. Orthotropous ovules are straight with all the parts of the ovule lined up in a long row producing an uncurved seed. Campylotropous ovules have a curved megagametophyte giving the seed a tight "C" shape.
The last ovule shape is called amphitropous, where the ovule is inverted and turned back 90 degrees on its stalk. In the majority of flowering plants, the zygote's first division is transversely oriented in regards to the long axis, this establishes the polarity of the embryo; the upper or chalazal pole becomes the main area of growth of the embryo, while the lower or micropylar pole produces the stalk-like suspensor that attaches to the micropyle. The suspensor absorbs and manufactures nutrients from the endosperm that are used during the embryo's growth; the main components of the embryo are: The cotyledons, the seed leaves, attached to the embryonic axis. There may be two; the cotyledons are the source of nutrients in the non-endospermic dicotyledons, in which case they replace the endosperm, are thick and leathery. In endospermic seeds the cotyledons are papery. Dicotyledons have the point of attachment opposite one another on the axis; the epicotyl, the embryonic axis above the point of attachment of the cotyledon.
The plumule, the tip of the epicotyl, has a feathery appearance due to the presence of young leaf primordia at the apex, will become the shoot upon germination. The hypocotyl, the embryonic axis below the point of attachment of the cotyledon, connecting the epicotyl and the radicle, being the stem-root transition zone; the radicle, the basal tip of the hy
Avena barbata is a species of wild oat known by the common name slender wild oat. It has edible seeds, it is a diploidized autotetraploid grass. Its diploid ancestors are A. hirtula Lag. and A. wiestii Steud, which are considered Mediterranean and desert ecotypes comprising a single species. A wiestii and A. hirtula are widespread in the Mediterranean Basin, growing in mixed stands with A. barbata, though they are difficult to tell apart. This is a winter annual grass with thin tillers growing up to 60 to 80 centimeters in maximum height, but known to sometimes grow taller; the bristly spikelets are 2 to 3 centimeters long, not counting the bent awn, up to 4 centimeters in length. Avena barbata reproduces by selfing in natural populations, with low rates of outcrossing. A. Barbata is native to the Mediterranean Basin; as an introduced species it occurs in other Mediterranean-like habitats of New Zealand, South Africa, Chile and Uruguay. In Europe it has been reported in Finland, Germany, Norway and Austria.
In North America it is an introduced species and noxious weed, where it is widespread in California. In California it has displaced native species of grass, it is found in Oregon, Hawaii, Nevada and New Mexico. Genetic evidence indicates that A. barbata in Argentina and California originated from Spain, during the Spanish colonization of the Americas. Californian populations of Avena barbata represent one of the most extensively studied examples of putative “ecotypes” in the plant literature, its population genetics and evolution have been extensively examined since 1967 in the laboratories of R. W. Allard and Subodh Jain and their many students in the 1960s, 1970's, 1980's, 1990’s at U. C. Davis, more by Robert Latta at the University of Dalhousie University in Nova Scotia; the general pattern that emerged from these earlier studies was that throughout the Central Valley of California, consisting of semiarid grasslands and oak savannahs, extending south to San Diego, populations of this species were dominated by a monomorphic phenotype possessing dark/black seeds with hairy lemmas, as well as smooth leaf sheaths.
This "ecotype" is called the "xeric" type. Populations outside the Central Valley, along the coastal strip, the intermontane regions of the coast ranges, the higher foothills of the Sierra Nevada mountains, were either monomorphic for white seeds with smooth lemmas and hairy leaf sheaths, or were polymorphic with varying mixtures of the seed and leaf sheath characters; these populations were either monomorphic or polymorphic for isozyme patterns and ribosomal DNA genotypes other than the xeric type. The mesic type has never been observed south of the same latitude as Monterey, either in coastal ranges, the Central Valley, or the foothills of the Sierras; when the morphological traits as well as the allozyme and ribosomal DNA genotypes were considered together, it is argued that there are six ecotypes in the otherwise "mesic" classification. Whole-plant studies showed that the xeric and mesic types differed from each other for many characters such as the flag leaf, primary stem height, number of tillers and number of seeds, dry weight, flowering time, with the mesic ecotype being larger and more fecund, than the xeric type.
It was further shown that xeric populations that were monomorphic for the seed and leaf sheath characters and allozymes had less genetic variation for quantitative genetics characters than mesic populations. With all genetic characters studied, xeric populations of the xeric ecotype were more similar to each other than they were to the mesic ecotype, the evidence indicated that the various ecotypes represented significant linkage disequilibrium and coadapted genetic complexes. For field identification purposes, the leaf sheath pubescence in the seedling stage and lemma color at seed maturity as well as the flag leaf dimensions would reliably separate the xeric from the mesic ecotypes throughout California. Early on it was speculated that the genetic patterns observed in A. barbata were correlated with rainfall and temperature. The general pattern at both a macro- and microgeographical scale was that the monomorphic "xeric" type occurred in those regions with between 250mm and 500mm of rainfall, while the polymorphic and monomorphic "mesic" populations occurred in those areas of California with greater than 500mm.
Regardless of the correlations found with the mesic and xeric genotypes with rainfall in California, greenhouse experiments have not shown that the xeric type has greater reproductive capacity or other physiologic superiority to the mesic under artificially induced wet or dry conditions. In fact Latta argues that the mesic type is superior to the xeric, may be supplanting the xeric in those areas where the xeric has been dominant, at least in Northern California. Avena barbata has been studied in Spain and Morocco by students and colleagues of R. W. Allard at U. C. Davis, Pèrez de la Vega and Pedro Garcia of the University of Leon, E. Nevo in Israel; the general pattern that has emerged is that there is more genetic variability in the Mediterranean populations than there are in Californian populat
Monocotyledons referred to as monocots, are flowering plants whose seeds contain only one embryonic leaf, or cotyledon. They constitute one of the major groups into which the flowering plants have traditionally been divided, the rest of the flowering plants having two cotyledons and therefore classified as dicotyledons, or dicots. However, molecular phylogenetic research has shown that while the monocots form a monophyletic group or clade, the dicots do not. Monocots have always been recognized as a group, but with various taxonomic ranks and under several different names; the APG III system of 2009 recognises a clade called "monocots" but does not assign it to a taxonomic rank. The monocots include about 60,000 species; the largest family in this group by number of species are the orchids, with more than 20,000 species. About half as many species belong to the true grasses, which are economically the most important family of monocots. In agriculture the majority of the biomass produced; these include not only major grains, but forage grasses, sugar cane, the bamboos.
Other economically important monocot crops include various palms and plantains, gingers and their relatives and cardamom, pineapple, water chestnut, leeks and garlic. Many houseplants are monocot epiphytes. Additionally most of the horticultural bulbs, plants cultivated for their blooms, such as lilies, irises, cannas and tulips, are monocots; the monocots or monocotyledons have, as the name implies, a single cotyledon, or embryonic leaf, in their seeds. This feature was used to contrast the monocots with the dicotyledons or dicots which have two cotyledons. From a diagnostic point of view the number of cotyledons is neither a useful characteristic, nor is it reliable; the single cotyledon is only one of a number of modifications of the body plan of the ancestral monocotyledons, whose adaptive advantages are poorly understood, but may have been related to adaption to aquatic habitats, prior to radiation to terrestrial habitats. Monocots are sufficiently distinctive that there has been disagreement as to membership of this group, despite considerable diversity in terms of external morphology.
However, morphological features that reliably characterise major clades are rare. Thus monocots are distinguishable from other angiosperms both in terms of their uniformity and diversity. On the one hand the organisation of the shoots, leaf structure and floral configuration are more uniform than in the remaining angiosperms, yet within these constraints a wealth of diversity exists, indicating a high degree of evolutionary success. Monocot diversity includes perennial geophytes such as ornamental flowers including and succulent epiphytes, all in the lilioid monocots, major cereal grains in the grass family and forage grasses as well as woody tree-like palm trees, bamboo and bromeliads, bananas and ginger in the commelinid monocots, as well as both emergent and aroids, as well as floating or submerged aquatic plants such as seagrass. Organisation and life formsThe most important distinction is their growth pattern, lacking a lateral meristem that allows for continual growth in diameter with height, therefore this characteristic is a basic limitation in shoot construction.
Although herbaceous, some arboraceous monocots reach great height and mass. The latter include agaves, palms and bamboos; this creates challenges in water transport. Some, such as species of Yucca, develop anomalous secondary growth, while palm trees utilise an anomalous primary growth form described as establishment growth; the axis undergoes primary thickening, that progresses from internode to internode, resulting in a typical inverted conical shape of the basal primary axis. The limited conductivity contributes to limited branching of the stems. Despite these limitations a wide variety of adaptive growth forms has resulted from epiphytic orchids and bromeliads to submarine Alismatales and mycotrophic Burmanniaceae and Triuridaceae. Other forms of adaptation include the climbing vines of Araceae which use negative phototropism to locate host trees, while some palms such as Calamus manan produce the longest shoots in the plant kingdom, up to 185 m long. Other monocots Poales, have adopted a therophyte life form.
LeavesThe cotyledon, the primordial Angiosperm leaf consists of a proximal leaf base or hypophyll and a distal hyperphyll. In monocots the hypophyll tends to be the dominant part in contrast to other angiosperms. From these, considerable diversity arises. Mature monocot leaves are narrow and linear, forming a sheath
The Pooideae are the largest subfamily of the grass family Poaceae, with over 4,200 species in 14 tribes and 200 genera. They include some major cereals such as wheat, oat and many lawn and pasture grasses, they are referred to as cool-season grasses, because they are distributed in temperate climates. All of them use the C3 photosynthetic pathway; the Pooideae are the sister group of the bamboos within the BOP clade, are themselves subdivided into 14 tribes. Relationships of tribes in the Pooideae according to a 2015 phylogenetic classification showing the bamboos as sister group
Apamea sordens, the rustic shoulder-knot or bordered apamea, is a moth of the family Noctuidae. It is distributed throughout Europe, East across the Palearctic to Central Asia and to China and Japan, it occurs in North America. This moth has a wingspan of 36 to 42 mm; the forewings are brown with indistinct markings except for the narrow black mark at the base of the wing which gives the species its common name. The hindwings are darker towards the margins, with prominent dark venation; this moth is attracted to light and sugar. Forewing dull lilac grey, flushed with fawn colour in median area, its flight season in the British Isles is June. The larva feeds on various grasses, including oats, barleys, timothy, ryes and wild rice; this species overwinters as a larva. It is grey brown with black tubercles, its habitat includes fields and steppe. Apamea sordens finitima Apamea sordens cerivana Apamea sordens sableana Mikkola, 2009 Chinery, M. Collins Guide to the Insects of Britain and Western Europe.
1986. Skinner, B. Colour Identification Guide to Moths of the British Isles. 1984. Rustic Shoulder-knot up UKmoths Funet Taxonomy Bug Guide Lepiforum.de
The Middle East is a transcontinental region centered on Western Asia and Egypt. Saudi Arabia is geographically the largest Middle Eastern nation; the corresponding adjective is Middle Eastern and the derived noun is Middle Easterner. The term has come into wider usage as a replacement of the term Near East beginning in the early 20th century. Arabs, Persians and Azeris constitute the largest ethnic groups in the region by population. Arabs constitute the largest ethnic group in the region by a clear margin. Indigenous minorities of the Middle East include Jews, Assyrians, Copts, Lurs, Samaritans, Shabaks and Zazas. European ethnic groups that form a diaspora in the region include Albanians, Circassians, Crimean Tatars, Franco-Levantines, Italo-Levantines. Among other migrant populations are Chinese, Indians, Pakistanis, Pashtuns and sub-Saharan Africans; the history of the Middle East dates back to ancient times, with the importance of the region being recognized for millennia. Several major religions have their origins in the Middle East, including Judaism and Islam.
The Middle East has a hot, arid climate, with several major rivers providing irrigation to support agriculture in limited areas such as the Nile Delta in Egypt, the Tigris and Euphrates watersheds of Mesopotamia, most of what is known as the Fertile Crescent. Most of the countries that border the Persian Gulf have vast reserves of crude oil, with monarchs of the Arabian Peninsula in particular benefiting economically from petroleum exports; the term "Middle East" may have originated in the 1850s in the British India Office. However, it became more known when American naval strategist Alfred Thayer Mahan used the term in 1902 to "designate the area between Arabia and India". During this time the British and Russian Empires were vying for influence in Central Asia, a rivalry which would become known as The Great Game. Mahan realized not only the strategic importance of the region, but of its center, the Persian Gulf, he labeled the area surrounding the Persian Gulf as the Middle East, said that after Egypt's Suez Canal, it was the most important passage for Britain to control in order to keep the Russians from advancing towards British India.
Mahan first used the term in his article "The Persian Gulf and International Relations", published in September 1902 in the National Review, a British journal. The Middle East, if I may adopt a term which I have not seen, will some day need its Malta, as well as its Gibraltar. Naval force has the quality of mobility; the British Navy should have the facility to concentrate in force if occasion arise, about Aden and the Persian Gulf. Mahan's article was reprinted in The Times and followed in October by a 20-article series entitled "The Middle Eastern Question," written by Sir Ignatius Valentine Chirol. During this series, Sir Ignatius expanded the definition of Middle East to include "those regions of Asia which extend to the borders of India or command the approaches to India." After the series ended in 1903, The Times removed quotation marks from subsequent uses of the term. Until World War II, it was customary to refer to areas centered around Turkey and the eastern shore of the Mediterranean as the "Near East", while the "Far East" centered on China, the Middle East meant the area from Mesopotamia to Burma, namely the area between the Near East and the Far East.
In the late 1930s, the British established the Middle East Command, based in Cairo, for its military forces in the region. After that time, the term "Middle East" gained broader usage in Europe and the United States, with the Middle East Institute founded in Washington, D. C. in 1946, among other usage. The description Middle has led to some confusion over changing definitions. Before the First World War, "Near East" was used in English to refer to the Balkans and the Ottoman Empire, while "Middle East" referred to Iran, the Caucasus, Central Asia, Turkestan. In contrast, "Far East" referred to the countries of East Asia With the disappearance of the Ottoman Empire in 1918, "Near East" fell out of common use in English, while "Middle East" came to be applied to the re-emerging countries of the Islamic world. However, the usage "Near East" was retained by a variety of academic disciplines, including archaeology and ancient history, where it describes an area identical to the term Middle East, not used by these disciplines.
The first official use of the term "Middle East" by the United States government was in the 1957 Eisenhower Doctrine, which pertained to the Suez Crisis. Secretary of State John Foster Dulles defined the Middle East as "the area lying between and including Libya on the west and Pakistan on the east and Iraq on the North and the Arabian peninsula to the south, plus the Sudan and Ethiopia." In 1958, the State Department explained that the terms "Near East" and "Middle East" were interchangeable, defined the region as including only Egypt, Israel, Jordan, Saudi Arabia, Kuwait and Qatar. The Associated Press Styleboo