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Starwort
Many, see text.
The genus Aster includes some 600 species of widely distributed flowering plants in the family Asteraceae. Aster comes from Greek word for "star", and refers to the shape of the flower head. Many of the species are popular garden plants because of their showy flower heads. The flowers of the Sea Aster (A. tripolium) are eaten by the larvae of the Wormwood Pug moth. The larvae of other Lepidoptera including Flame Shoulder and Hummingbird Hawk-moth sometimes eats the foliage of asters.
The genus Aster is now generally restricted to the Old World species, with Aster amellus being the type species of the genus (and of the family Asteraceae). The New World species have now been reclassified in the genera Almutaster, Canadanthus, Doellingeria, Eucephalus, Eurybia, Ionactis, Oligoneuron, Oreostemma, Sericocarpus and Symphyotrichum (see : List of Aster synonyms), but are still widely referred to as "Asters" in the horticultural trades.
Some common species are:
- Aster alpinus
- Aster amellus (European Michaelmas Daisy or Italian Aster)
- Aster cordifolius (Blue Wood Aster)
- Aster divaricatus (White Wood Aster)
- Aster ericoides (Heath Aster)
- Aster laevis
- Aster lateriflorus
- Aster novae-angliae (New England Aster)
- Aster novi-belgii (New York Aster)
- Aster pilosus (Frost Aster)
- Aster pringlei
- Aster sibericus
- Aster tataricus
- Aster tongolensis
- Aster tripolium (Sea Aster)
The China aster is in a related genus, Callistephus.
Image:AsterNovi-belgii-flower-1mb.jpg|New York Aster (Aster novi-belgii)
Image:Aster tongolensis0.jpg|Aster tongolensis
Image:White heath aster.jpg|Heath aster (Aster ericoides)
Image:Aster flower.jpg|Asters come in many different colors and varieties
Category:Asteraceae
Flowering plant
Magnoliopsida - Dicots
Liliopsida - Monocots
The flowering plants (also called angiosperms) are a major group of land plants. They comprise one of the two groups in the seed plants: the flowering plants cover their seeds by including them in a true fruit. They bear the reproductive organs in a structure called a flower; the ovule is enclosed within a carpel, which will lead to a fruit.
In the other major group of seed plants, called gymnosperms, the ovule is not enclosed at pollination and the seeds are not in a true fruit, although occasionally fleshy structures may cover the seed (e.g. Taxus).
History
The botanical term "Angiosperm" (Greek: αγγειον, receptacle, and σπερμα, seed) was coined in the form Angiospermae by Paul Hermann in 1690, as the name of that one of his primary divisions of the plant kingdom, which included flowering plants possessing seeds enclosed in capsules, in contradistinction to 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 Carolus Linnaeus with the same sense, but with restricted application, in the names of the orders of his class Didynamia. Its use with any approach to its modern scope only became possible after Robert Brown had established in 1827 the existence of truly naked ovules in the Cycadeae and Coniferae, entitling them to be correctly called Gymnosperms. From that time onwards, so long as these Gymnosperms were, as was usual, reckoned as dicotyledonous flowering plants, the term Angiosperm was used antithetically by botanical writers, but with varying limitation, as a group-name for other dicotyledonous plants.
The advent in 1851 of Hofmeister's brilliant discovery of the changes proceeding in the embryo-sac of flowering plants, and his determination of the correct relationships of these with the Cryptogamia, fixed the position of Gymnosperms as a class distinct from Dicotyledons, and the term Angiosperm then gradually came to be accepted as the suitable designation for the whole of the flowering plants other than Gymnosperms, and as including therefore the classes of Dicotyledons and Monocotyledons. This is the sense in which the term is nowadays received and in which it is used here.
Origins
The trend of the evolution of the plant kingdom has been in the direction of the establishment of a vegetation of fixed habit and adapted to the vicissitudes of a life on land, and the Angiosperms are the highest expression of this evolution and constitute the dominant vegetation of the earth's surface at the present epoch. There is no land-area from the poles to the equator, where plant-life is possible, upon which Angiosperms are not found. They also occur abundantly in the shallows of rivers and fresh-water lakes, and in less number in salt lakes and in the sea; such aquatic Angiosperms are not, however, primitive forms, but are derived from immediate land-ancestors. Associated with this diversity of habitat is great variety in general form and manner of growth. The familiar duckweed which covers the surface of a pond consists of a tiny green "thalloid" shoot, one, that is, which shows no distinction of parts—stem and leaf, and a simple root growing vertically downwards into the water. The great forest-tree has a shoot, which in the course perhaps of hundreds of years, has developed a wide-spreading system of trunk and branches, bearing on the ultimate twigs or branchlets innumerable leaves, while beneath the soil a widely-branching root-system covers an area of corresponding extent. Between these two extremes is every conceivable gradation, embracing aquatic and terrestrial herbs, creeping, erect or climbing in habit, shrubs and trees, and representing a much greater variety than is to be found in the other subdivision of seed-plants, the Gymnosperms.
The first evidence of angiosperms appears in the fossil record approximately 140 million years ago, during the Jurassic period (203-135 million years ago). Based on current evidence, it seems that the ancestors of the angiosperms and the Gnetophytes diverged from one another during the late Triassic (220-202 million years ago). Fossil plants with some identifiable angiosperm characteristics appear in the Jurassic and early Cretaceous (135-65 million years ago), but in relatively few and primitive forms. The great angiosperm radiation, when a great diversity of angiosperms appear in the fossil record, occurred in the mid-Cretaceous (approximately 100 million years ago). By the late Cretaceous, angiosperms appear to have become the predominant group of land plants, and many fossil plants recognizable as belonging to modern families (including beech, oak, maple, and magnolia) appeared.
Classification
The flowering plants are usually treated as a division. As this is a group above the rank of family there is a free choice of name: Art 16 of the ICBN allows either a descriptive name or a name based on a generic name. The favorite name in the latter category is Magnoliophyta (at the rank of division, based on the Magnolia. The most popular descriptive name is Angiospermae (Angiosperms), with Anthophyta ("flowering plants") a second choice.
The internal classification of this group has undergone considerable revision as ideas about their relationships change. The Cronquist system, proposed by Arthur Cronquist in 1981, is still widely used but is no longer believed to reflect phylogeny. A general consensus about how the flowering plants should be arranged has only recently begun to emerge, through the work of the Angiosperm Phylogeny Group, who published an influential reclassification of the angiosperms in 1998. An update incorporating more recent research was published as APG (2003) and is available at the Wikipedia Tree of Life/Update of the Angiosperm Phylogeny Group.
Traditionally, the flowering plants are divided into two groups, which in the Cronquist system are called Magnoliopsida (at the rank of class, based on Magnolia) and Liliopsida (at the rank of class, based on Lilium). Much more popular are their descriptive names (as allowed by Art 16 of the ICBN): Dicotyledones (some prefer Dicotyledoneae) and Monocotyledones (some prefer Monocotyledoneae), which have been in use for very long. In English a member of either group may be called a "dicotyledon" (plural "dicotyledons") and "monocotyledon" (plural "monocotyledons"), or more popularly "dicot" (plural "dicots") and "monocot" (plural "monocots"). These names derive from the fact that the dicots often (but not always) have two cotyledons (embryonic leaves) within each seed, while the monocots typically will have one only. From a diagnostic point of view the number of cotyledons is neither a particularly handy nor reliable character.
Recent studies show that the monocots are a "good" group (a holophyletic or monophyletic group), while the dicots are not (a paraphyletic group). However, within the dicots a "good" group exists, which includes most of the dicots. This new group is semi-informally called the "eudicots" or "tricolpates". The name "tricolpates" derives from the type of pollen found throughout this group. The name eudicots is formed by preceding "dicot" by the prefix "eu-" (greek 'eu'= "true"), as the eudicots share the characters traditionally attributed to the dicots, such a four- or five-merous flowers. The uninitiate may be tempted to jump to the conclusion that "eudicot" is short for "eudicotyledon" but it is not: the name is eudicot. A formal name that is sometimes used for this group is Rosopsida (at the rank of class, based on Rosa). Separating this group of eudicots from the rest of the (former) dicots leaves a remainder, which sometimes are called informally "palaeodicots" (the prefix "palaeo-" means old, and derives from the classic greek). As this remainder group is not a "good" group this is a term of convenience only.
Families of flowering plants
The most diverse families of flowering plants, in order of number of species, are:
palaeodicot flower]]
# Asteraceae or Compositae (Daisy family): 26,000 species
# Orchidaceae (Orchid family): 20,000 (possibly 30,000)
# Fabaceae or Leguminosae (Pea family): 17,000
# Poaceae or Gramineae (Grass family): 9,000
# Rubiaceae (Madder family): 7,000
# Euphorbiaceae (Spurge family): 5,000
# Malvaceae (Mallow family): 4,300
# Cyperaceae (Sedge family): 4,000
In the list above (showing only the 8 largest families), the Orchidaceae, Poaceae, and Cyperaceae are monocot families; the others are dicot families. The total number of families in the flowering plants is over 460.
Internal structure
In internal structure the variety of tissue-formation far exceeds that found in Gymnosperms. The vascular bundles of the stem belong to the collateral type, that is to say, the elements of the wood or xylem and the bast or phloem stand side by side on the same radius. In the larger of the two great groups into which the Angiosperms are divided, the Dicotyledons, the bundles in the very 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 (interfascicular cambium) a complete ring is formed, and a regular periodical increase in thickness results from it by the development of xylem on the inside and phloem on the outside. The soft phloem soon becomes crushed, but the hard wood persists, and forms the great 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—the so-called annual rings. In the smaller group, the Monocotyledons, the bundles are more numerous in the young stem and scattered through the ground tissue. Moreover they contain no cambium and the stem once formed increases in diameter only in exceptional cases.
Vegetative organs
As in Gymnosperms, branching is monopodial; dichotomy or the forking of the growing point into two equivalent branches which replace the main stem, is absent both in the case of the stem and the root. The leaves show a remarkable variety in form, but are generally small in comparison with the size of the plant; exceptions occur in some Monocotyledons, e.g. in the Aroid family, where in some genera the plant produces one huge, much-branched leaf each season.
In rare cases the main axis is unbranched and ends in a flower, as, for instance, in the tulip, where scale-leaves, forming the underground bulb, green foliage-leaves and coloured floral leaves are borne on one and the same axis. Generally, flowers are formed only on shoots of a higher order, often only on the ultimate branches of a much branched system. A potential branch or bud, either foliage or flower, is formed in the axil of each leaf; sometimes more than one bud arises, as for instance in the walnut, where two or three stand in vertical series above each leaf. Many of the buds remain dormant, or are called to development under exceptional circumstances, such as the destruction of existing branches. For instance, the clipping of a hedge or the lopping of a tree will cause to develop numerous buds which may have been dormant for years. Leaf-buds occasionally arise from the roots, when they are called adventitious; this occurs in many fruit trees, poplars, elms and others. For instance, the young shoots seen springing from the ground around an elm are not seedlings but root-shoots. Frequently, as in many Dicotyledons, the primary root, the original root of the seedling, persists throughout the life of the plant, forming, as often in biennials, a thickened tap-root, as in carrot, or in perennials, a much-branched root system. In many Dicotyledons and most Monocotyledons, the primary root soon perishes, and its place is taken by adventitious roots developed from the stem.
The flower, fruit, and seed
- See main article: Flower
The characteristic feature of angiosperms is the flower, which shows remarkable variation in form and elaboration, and provides the most trustworthy external characteristics for establishing relationships among angiosperm species. The function of the flower is that of ensuring fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf. Occasionally, as in violet, a flower arises singly in the axil of an ordinary foliage-leaf. However, more typically, the flower-bearing portion of the plant is sharply distinguished from the foliage-bearing or vegetative portion, and forms a more or less elaborate branch-system called an inflorescence.
As in gymnosperms, spores produced by flowers are of two kinds: microspores or pollen-grains, borne in the stamens (or microsporophylls) and megaspores, in which the egg-cell is developed, contained in the ovule and enclosed in the carpel (or megasporophyll). The flower may consist only of these spore-bearing parts, as in willow, where each flower comprises only a few stamens or two carpels. Usually, however, other structures are present and serve both to protect the sporophylls and to form an attractive envelope. The individual members of these surrounding structures are called sepals and petals (or tepals in a flower such as Michelia). The outer series (calyx of sepals) is usually green and leaf-like, and functions to protect the rest of the flower, especially in the bud. The inner series (corolla of petals) is generally white or brightly coloured, and more delicate in structure, and functions in attracting a particular insect or bird by agency of which pollination is effected. This attraction involves colour and scent, and frequently also nectar which is secreted in some part of the flower. These characteristics that attract pollinators account for the popularity of flowers and flowering plants among humans.
Flowering plant sexuality
- See main article: Plant sexuality
Flowers are the reproductive structures of flowering plants. The "male" organ is the stamen or androecium, which produces pollen (male spores) in anthers. The "female" organ is the carpel or gynoecium, which contains the egg (female gamete) and is the site of fertilization. While the majority of flowers are perfect or hermaphrodite (having both male and female parts in the same flower structure), 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 easily transfer pollen to the pistil (receptive part of the carpel). Homomorphic flowers may employ a biochemical (physiological) 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.
Fertilization
At the period of fertilization the embryo-sac lies in close proximity to the opening of the micropyle, into which the pollen-tube has penetrated, the separating cell-wall becomes absorbed, and the male or sperm-cells are ejected into the embryo-sac. Guided by the synergidae one male-cell passes into the oosphere with which it fuses, the two nuclei uniting, while the other fuses with the definitive nucleus, or, as it is also called, the endosperm nucleus. This remarkable double fertilization as it has been called, although only recently discovered, has been proved to take place in widely-separated families, and both in Monocotyledons and of a prothallium after a pause following the reinvigorating union of the polar nuclei. This view is still maintained by those who differentiate two acts of fertilization within the embryo-sac, and regard that of the egg by the first male-cell, as the true or generative fertilization, and that of the polar nuclei by the second male gamete as a vegetative fertilization which gives a stimulus to development in correlation with the other. If, on the other hand, the endosperm is the product of an act of fertilization as definite as that giving rise to the embryo itself, we have to recognize that twin-plants are produced within the embryo-sac—one, the embryo, which becomes the angiospermous plant, the other, the endosperm, a short-lived, undifferentiated nurse to assist in the nutrition of the former, even as the subsidiary embryos in a pluri-embryonic Gymnosperm may facilitate the nutrition of the dominant one. If this is so, and the endosperm like the embryo is normally the product of a sexual act, hybridization will give a hybrid endosperm as it does a hybrid embryo, and herein (it is suggested) we may have the explanation of the phenomenon of xenia observed in the mixed endosperms of hybrid races of maize and other plants, regarding which it has only been possible hitherto to assert that they were indications of the extension of the influence of the pollen beyond the egg and its product. This would not, however, explain the formation of fruits intermediate in size and colour between those of crossed parents. The signification of the coalescence of the polar nuclei is not explained by these new facts, but it is noteworthy that the second male-cell is said to unite sometimes with the apical polar nucleus, the sister of the egg, before the union of this with the basal polar one.
The idea of the endosperm as a second subsidiary plant is no new one; it was suggested long ago in explanation of the coalescence of the polar nuclei, but it was then based on the assumption that these represented male and female cells, an assumption for which there was no evidence and which was inherently improbable. The proof of a coalescence of the second male nucleus with the definitive nucleus gives the conception a more stable basis. The antipodal cells aid more or less in the process of nutrition of the developing embryo, and may undergo multiplication, though they ultimately disintegrate, as do also the synergidae. As in Gymnosperms and other groups an interesting qualitative change is associated with the process of fertilization. The number of chromosomes (see Plant cytology) in the nucleus of the two spores, pollen-grain and embryo-sac, is only half the number found in an ordinary vegetative nucleus; and this reduced number persists in the cells derived from them. The full number is restored in the fusion of the male and female nuclei in the process of fertilization, and remains until the formation of the cells from which the spores are derived in the new generation.
In several natural orders and genera departures from the course of development just described have been noted. In the natural Order Rosaceae, the Series Querciflorae, and the very anomalous Genus Casuarina and others, instead of a single macrospore a more or less extensive sporogenous tissue is formed, but only one cell proceeds to the formation of a functional female cell. In Casuarina, Juglans and the Order Corylaceae, the pollen-tube does not enter by means of the micropyle, but passing down the ovary wall and through the placenta, enters at the chalazal end of the ovule. Such a method of entrance is styled chalazogamic, in contrast to the porogamic or ordinary method of approach by means of the micropyle.
Embryology
The result of fertilization is the development of the ovule into the seed. By the segmentation of the fertilized egg, now invested by cell-membrane, the embryo-plant arises. A varying number of transverse segment-walls transform it into a pro-embryo—a cellular row of which the cell nearest the micropyle becomes attached to the apex of the embryo-sac, and thus fixes the position of the developing embryo, while the terminal cell is projected into its cavity. In Dicotyledons the shoot of the embryo is wholly derived from the terminal cell of the pro-embryo, from the next cell the root arises, and the remaining ones form the suspensor. In many Monocotyledons the terminal cell forms the cotyledonary portion alone of the shoot of the embryo, its axial part and the root being derived from the adjacent cell; the cotyledon is thus a terminal structure and the apex of the primary stem a lateral one—a condition in marked contrast with that of the Dicotyledons. In some Monocotyledons, however, the cotyledon is not really terminal. The primary root of the embryo in all Angiosperms points towards the micropyle. The developing embryo at the end of the suspensor grows out to a varying extent into the forming endosperm, from which by surface absorption it derives good material for growth; at the same time the suspensor plays a direct part as a carrier of nutrition, and may even develop, where perhaps no endosperm is formed, special absorptive "suspensor roots" which invest the developing embryo, or pass out into the body and coats of the ovule, or even into the placenta. In some cases the embryo or the embryo-sac sends out suckers into the nucellus and ovular integument. As the embryo develops it may absorb all the food material available, and store, either in its cotyledons or in its hypocotyl, what is not immediately required for growth, as reserve-food for use in germination, and by so doing it increases in size until it may fill entirely the embryo-sac; or its absorptive power at this stage may be limited to what is necessary for growth and it remains of relatively small size, occupying but a small area of the embryo-sac, which is otherwise filled with endosperm in which the reserve-food is stored. There are also intermediate states. The position of the embryo in relation to the endosperm varies, sometimes it is internal, sometimes external, but the significance of this has not yet been established.
The formation of endosperm starts, as has been stated, from the endosperm nucleus. Its segmentation always begins before that of the egg, and thus there is timely preparation for the nursing of the young embryo. If in its extension to contain the new formations within it the embryo-sac remains narrow, endosperm formation proceeds upon the lines of a cell-division, but in wide embryo-sacs the endosperm is first of all formed as a layer of naked cells around the wall of the sac, and only gradually acquires a pluricellular character, forming a tissue filling the sac. The function of the endosperm is primarily that of nourishing the embryo, and its basal position in the embryo-sac places it favourably for the absorption of food material entering the ovule. Its duration varies with the precocity of the embryo. It may be wholly absorbed by the progressive growth of the embryo within the embryo-sac, or it may persist as a definite and more or less conspicuous constituent of the seed. When it persists as a massive element of the seed its nutritive function is usually apparent, for there is accumulated within its cells reserve-food, and according to the dominant substance it is starchy, oily, or rich in cellulose, mucilage or proteid. In cases where the embryo has stored reserve food within itself and thus provided for self-nutrition, such endosperm as remains in the seed may take on other functions, for instance, that of water-absorption.
Some deviations from the usual course of development may be noted. Parthenogenesis, or the development of an embryo from an egg-cell without the latter having been fertilized, has been described in species of Thalictrum, Antennaria and Alchemilla. Polyembryony is generally associated with the development of cells other than the egg-cell. Thus in Erythronium and Limnocharis the fertilized egg may form a mass of tissue on which several embryos are produced. Isolated cases show that any of the cells within the embryo-sac may exceptionally form an embryo, e.g. the synergidae in species of Mimosa, Iris and Allium, and in the last-mentioned the antipodal cells also. In Coelebogyne (Euphorbiaceae) and in Funkia (Liliaceae) polyembryony results from an adventitious production of embryos from the cells of the nucellus around the top of the embryo-sac. In a species of Allium, embryos have been found developing in the same individual from the egg-cell, synergids, antipodal cells and cells of the nucellus. In two Malayan species of Balanophora, the embryo is developed from a cell of the endosperm, which is formed from the upper polar nucleus only, the egg apparatus becoming disorganized. The last-mentioned case has been regarded as representing an apogamous development of the sporophyte from the gametophyte comparable to the cases of apogamy described in Ferns. But the great diversity of these abnormal cases as shown in the examples cited above suggests the use of great caution in formulating definite morphological theories upon them.
Fruit and seed
As the development of embryo and endosperm proceeds within the embryo-sac, its wall enlarges and commonly absorbs the substance of the nucellus (which is likewise enlarging) to near its outer limit, and combines with it and the integument to form the seed-coat; or the whole nucellus and even the integument may be absorbed. In some plants the nucellus is not thus absorbed, but itself becomes a seat of deposit of reserve-food constituting the perisperm which may coexist with endosperm, as in the water-lily order, or may alone form a food-reserve for the embryo, as in Canna. Endospermic food-reserve has evident advantages over perispermic, and the latter is comparatively rarely found and only in non-progressive series. Seeds in which endosperm or perisperm or both exist are commonly called albuminous or endospermic, those in which neither is found are termed exalbuminous or exendospermic. These terms, extensively used by systematists, only refer, however, to the grosser features of the seed, and indicate the more or less evident occurrence of a food-reserve; many so-called exalbuminous seeds show to microscopic examination a distinct endosperm which may have other than a nutritive function. The presence or absence of endosperm, its relative amount when present, and the position of the embryo within it, are valuable characters for the distinction of orders and groups of orders. Meanwhile the ovary wall has developed to form the fruit or pericarp, the structure of which is closely associated with the manner of distribution of the seed. Frequently the influence of fertilization is felt beyond the ovary, and other parts of the flower take part in the formation of the fruit, as the floral receptacle in the apple, strawberry and others. The character of the seed-coat bears a definite relation to that of the fruit. Their function is the twofold one of protecting the embryo and of aiding in dissemination; they may also directly promote germination. If the fruit is a dehiscent one and the seed is therefore soon exposed, the seed-coat has to provide for the protection of the embryo and may also have to secure dissemination. On the other hand, indehiscent fruits discharge these functions for the embryo, and the seed-coat is only slightly developed.
Economic importance
Flowering plants provide a very high percentage of the base food for human use, whether directly or through livestock feed. Of all the families of flowering plants, the Poaceae, or grass family, is by far the most important, providing the bulk of all feedstocks (rice, corn (maize), wheat, barley, rye, oats, millet, sugar cane, sorghum), with the Fabaceae, or legume family, in second place. Also of high importance are the Solanaceae, or nightshade family (potatoes, tomatoes, and peppers, among others), the Cucurbitaceae, or gourd family (also including pumpkins and melons), the Brassicaceae, or mustard family (including rapeseed and cabbage), and the Apiaceae, or parsley family. Many of our fruits come from the Rutaceae, or rue family, and the Rosaceae (rose family, including apples, pears, cherries, apricots, plums, etc).
In some parts of the world, certain single species assume paramount importance because of their variety of uses. An example is the coconut (Cocos nucifera) on Pacific atolls. Another example is the olive (Olea europaea) in the Mediterranean.
Flowering plants also provide economic resources in the form of wood, paper, fiber (cotton, flax, and hemp, among others), medicines (digitalis, camphor), decorative and landscaping plants, and many, many other uses.
See also
- List of flowers
References and external links
- Angiosperm Phylogeny Group (2003). An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society 141: 399-436. [http://www.blackwell-synergy.com/links/doi/10.1046/j.1095-8339.2003.t01-1-00158.x/full/ Available online].
- [http://tolweb.org/tree?group=Angiosperms&contgroup=Spermatopsida Angiosperms] – Tree of Life Web Project
- Cronquist, Arthur. (1981) An Integrated System of Classification of Flowering Plants. Columbia Univ. Press, New York.
- [http://www.news.harvard.edu/gazette/1999/12.16/angiosperms.html Oldest Known Flowering Plants Identified By Genes], William J. Cromie, Harvard Gazette, December 16, 1999.
- Stevens, P.F. (2001 onwards). [http://www.mobot.org/MOBOT/Research/APweb/welcome.html Angiosperm Phylogeny Website] at Missouri Botanical Garden.
- [http://delta-intkey.com/angio/ L. Watson and M.J. Dallwitz (1992 onwards). The families of flowering plants: descriptions, illustrations, identification, information retrieval.] http://delta-intkey.com
Category:Magnoliophyta
sort31 Angiospermae
sort31 Angiospermae
Category:Sexuality
Category:Pollination
ko:속씨식물
ms:Angiosperm
ja:被子植物門
th:ไม้ดอก
Greek language
Greek (Greek Ελληνικά, IPA – "Hellenic") is an Indo-European language with a documented history of 3,500 years. Today, it is spoken by 15 million people in Greece, Cyprus, the former Yugoslavia, particularly The Former Yugoslav Republic of Macedonia, Bulgaria, Albania and Turkey. There are also many Greek emigrant communities around the world, such as those in Melbourne, Australia which is the third-largest Greek-populated city in the world, after Athens and Thessaloniki.
Greek has been written in the Greek alphabet, the first true alphabet, since the 9th century B.C. and before that, in Linear B and the Cypriot syllabaries.
Greek literature has a long and rich tradition.
History
This article does not cover the reconstructed history of Greek prior to the use of writing. For more information, see main article on Proto-Greek language.
Greek has been spoken in the Balkan Peninsula since the 2nd millennium BC. The earliest evidence of this is found in the Linear B tablets dating from 1500 BC. The later Greek alphabet (q.v.) is unrelated to Linear B, and was derived from the Phoenician alphabet (abjad); with minor modifications, it is still used today. Greek is conventionally divided into the following periods:
- Mycenean Greek: the language of the Mycenean civilisation. It is recorded in the Linear B script on tablets dating from the 16th century BC onwards.
- Classical Greek (also known as Ancient Greek): In its various dialects was the language of the Archaic and Classical periods of Greek civilisation. It was widely known throughout the Roman empire. Classical Greek fell into disuse in western Europe in the Middle Ages, but remained known in the Byzantine world, and was reintroduced to the rest of Europe with the Fall of Constantinople and Greek migration to Italy.
- Hellenistic Greek (also known as Koine Greek): The fusion of various ancient Greek dialects with Attic (the dialect of Athens) resulted in the creation of the first common Greek dialect, which gradually turned into one of the world's first international languages. Koine Greek can be initially traced within the armies and conquered territories of Alexander the Great, but after the Hellenistic colonisation of the known world, it was spoken from Egypt to the fringes of India. After the Roman conquest of Greece, an unofficial diglossy of Greek and Latin was established in the city of Rome and Koine Greek became a first or second language in the Roman Empire. Through Koine Greek it is also traced the origin of Christianity, as the Apostles used it to preach in Greece and the Greek-speaking world. It is also known as the Alexandrian dialect, Post-Classical Greek or even New Testament Greek (after its most famous work of literature).
- Medieval Greek: The continuation of Hellenistic Greek during medieval Greek history as the official and vernacular (if not the literary nor the ecclesiastic) language of the Byzantine Empire, and continued to be used until, and after the fall of that Empire in the 15th century. Also known as Byzantine Greek.
- Modern Greek: Stemming independently from Koine Greek, Modern Greek usages can be traced in the late Byzantine period (as early as 11th century).
Two main forms of the language have been in use since the end of the medieval Greek period: Dhimotikí (Δημοτική), the Demotic (vernacular) language, and Katharévousa (Καθαρεύουσα), an imitation of classical Greek, which was used for literary, juridic, and scientific purposes during the 19th and early 20th centuries. Demotic Greek is now the official language of the modern Greek state, and the most widely spoken by Greeks today.
It has been claimed that an "educated" speaker of the modern language can understand an ancient text, but this is surely as much a function of education as of the similarity of the languages. Still, Koinē , the version of Greek used to write the New Testament and the Septuagint, is relatively easy to understand for modern speakers.
Greek words have been widely borrowed into the European languages: astronomy, democracy, philosophy, thespian, etc. Moreover, Greek words and word elements continue to be productive as a basis for coinages: anthropology, photography, isomer, biomechanics etc. and form, with Latin words, the foundation of international scientific and technical vocabulary. See English words of Greek origin, and List of Greek words with English derivatives.
Classification
Greek is an independent branch of the Indo-European language family. The ancient languages which were probably most closely related to it, Ancient Macedonian language (which may be regarded as a dialect of Greek) and Phrygian, are not well enough documented to permit detailed comparison. Among living languages, Armenian seems to be the most closely related to it.
Geographic distribution
Modern Greek is spoken by about 15 million people mainly in Greece and Cyprus. There are also Greek-speaking populations in Georgia, Ukraine, Egypt, Turkey, Albania, Former Yugoslav Republic of Macedonia and Southern Italy. The language is spoken also in many other countries where Greeks have settled, including Armenia, Australia, Austria, Belgium, Bulgaria, Canada, Denmark, France, Germany, Netherlands, Sweden, United Kingdom, and the United States.
Official status
Greek is the official language of Greece where it is spoken by about 99.5% of the population. It is also, alongside Turkish, the official language of Cyprus. Due to the membership of Greece and Cyprus, Greek is one of the 20 official languages of the European Union.
Phonology
This section generally describes the post-Classic phonology of the Greek language.
:All phonetic transcriptions in this section use the International Phonetic Alphabet
Vowel sounds
Greek has 5 vowel sounds, all phonemic:
InflorescenceAn inflorescence is a group or cluster of flowers on a branch of a plant. In botany, the term refers to the way individual flowers are arranged on the axis (floral stem). An inflorescence is said to be indeterminate if the number of flowers may increase after the first flower opens, even while others are opening, and determinate if the number of flowers cannot increase after the first flower opens. With indeterminate inflorescent clusters, the most proximal flowers (ie. those closest to the base) open first; in the case of determinate flower clusters, the most distal flowers (ie. those furthest from the stem) open first.
indeterminate
There are numerous kinds of inflorescences, some characteristic of families or orders of plants. Following is a list of terms used to describe inflorescences with links to examples:
- A corymb is a racemose (see raceme) inflorescence that is flat-topped or convex because the outer pedicels are progressively longer than the inner ones (see also umbel).
- A cyme is a class of determinate inflorescences characterized by the terminal flower blooming first.
- A head is a dense, indeterminate inflorescence of [http://en.wiktionary.org/wiki/Sessile sessile] or subsessile flowers crowded on a compound receptacle; sometimes called a capitulum. Characteristic of the Asteraceae.
- A panicle is a branched, indeterminate inflorescence with pedicellate (having short floral stalks) flowers on the secondary branches.
- A raceme is an unbranched, indeterminate inflorescence with pedicellate (having short floral stalks) flowers along the axis. Compare with spike.
- A spadix is a stalk with flowers densely arranged around it, enclosed or accompanied by a spathe. It is characteristic of the Araceae.
- A spike is an unbranched, indeterminate inflorescence with sessile flowers arranged along the axis. Compare with raceme.
- An umbel is a type of raceme with a short axis and multiple floral pedicels of equal length that appear to arise from a common point. Inflorescence characteristic of the Apiaceae. A compressed cyme is called umbelliform if it resembles an umbel.
Image:Inflorescences.JPG
Category:Plant morphology
ja:花序
Larva
A larva (Latin; plural larvae) is a juvenile form of animal with indirect development, undergoing metamorphosis (for example, insects or amphibians).
The larva can look completely different from the adult form, for example, a caterpillar differs from a butterfly. Larvae often have special (larval) organs which do not occur in the adult form. The larvae of some species can become pubescent and not further develop into the adult form (for example, in some newts). This is called neoteny.
It is a misunderstanding that the larval form always reflects the groups evolutionary history. It could be the case, but often the larval stage has evolved secondarily, like in insects. In these cases the larval form might differ more from the group's common origin than the adult form. The primary larval form it does not necessarily show how an animal's ancestors looked like, since this stage often has evolved in its own direction just as the adult form has.
Names of various kinds of larvae:
Category:Developmental biology
simple:Larva
Moth
A moth is an insect closely related to the butterfly. Both are of the order Lepidoptera. The division of Lepidopterans into moths and butterflies is a popular taxonomy, not a scientific one. Sometimes the names "Rhopalocera" (butterflies) and "Heterocera" (moths) are used to formalise the popular distinction.
Most species of moths are nocturnal, but there are crepuscular and diurnal species. They can be distinguished from butterflies in several ways.
People who study butterflies and/or moths are called lepidopterists; the study of butterflies is known as butterflying, and the study of moths mothing, the latter giving rise to the term mother for someone who takes part in this activity – sometimes written with a hyphen inserted (moth-er) or as moffer to distinguish it from the word for a female parent (in spoken English, confusion does not arise as the two are pronounced differently).
Economic significance of moths
mothing
Moths, and more particularly their caterpillars are a major agricultural pest in many parts of the world. The caterpillar of the Gypsy moth causes severe damage to forests in North East USA, where it is an exotic species. The Codling moth also does extensive damage, especially to fruit farms.
Other moths are commonly regarded as pests because their larvae eat fabric such as clothes and blankets made from natural proteinaceous fibers such as wool or silk. They are less likely to eat mixed materials containing artificial fibres. There are some reports that they can be repelled by the scent of wood from juniper and cedar, by lavender or by other natural oils. However, many consider this unlikely to prevent infestation. Naphthalene (the chemical used in mothballs) is considered more effective, but there are concerns over its effects on health. Freezing items infested with moth larvae will not kill them.
Moths are sturdy and usually require larger amount of pesticide to kill them than mosquitos or flies.
Other moths are farmed. Especially the Silkworm (the larva of a moth) is farmed for the silk with which it builds its cocoon. The silk industry produces over 130 million kg of raw silk, worth about 250 million US dollars worldwide.
Attraction to light
cocoon
Moths are apparently attracted to light, or more specifically, are known to circle bright objects. The reason for this behaviour is not known. It may be moths navigate by maintaining a constant angular relationship to a bright celestial light (such as the moon), but on encountering a bright artificial light it navigates maintaining a constant angle to the light resulting in the moth flying in a spiral until it hits the light source.
However, researchers such as Henry Hsiao suggest the reason for moths circling lights has to do with a visual distortion called a Mach band. Henry Hsiao conjectures that moths, as nocturnal creatures, fly towards the darkest part of the sky in pursuit of safety. Moths are thus inclined to circle ambient objects in the Mach band region, usually at a radius of about one foot, depending on the species.
Night blooming flowers usually depend on moths (or bats) for pollination, and artificial lighting can draw moths away from the flowers, affecting the plant's ability to reproduce. Light pollution is coming under increasing scrutiny as a source of many subtle ecological changes.
Moth species
Large and dramatic Moth species include:
- Death's-head Hawkmoth Acherontia sp.
- Luna Moth Actias luna
- Atlas moth Attacus atlas The largest moth in the world
- Emperor Gum Moth Opodiphthera eucalypti
Moths that are of economic significance include:
- Gypsy moth Lymantria dispar
- Cotton bollworm or corn earworm a major agricultural pest
- Codling moth
- Light brown apple moth Epiphyas postvittana
- The silkworm Bombyx mori is the larva of a moth.
Other notable moths:
- Peppered moth Biston betularia The subject of a now well known study in evolution.
See also
- Difference between a butterfly and a moth
- List of moths
Gallery
Image:Lepidoptere(s).jpg|Lepidopteran on a flower.
Image:Moth.jpg|A moth
Image:Case moth.jpg|Case Moth
Image:Case moth02.jpg|Case Moth
Image:Looper moth.jpg|Looper Moth
Image:LeopardMoth.jpg|Giant Leopard Moth
Image:Rosy Maple Moth.png|Rosy Maple Moth (Dryocampa rubicunda)
Image:Moth-Georgia-Oct12005.jpg|Grammia parthenice Tiger Moth
Image:Nyctemera.amica.jpg|Nyctemera amica
Image:Chelepteryx.collesi.jpg|Chelepteryx collesi (Gray) (Anthelidae)
Image:Chelepteryx.collesi.02.jpg|Chelepteryx collesi (Gray) (Anthelidae)
External links
- [http://www.pollinator.com/plant_pol/caterpillars/barbarea_verna2.htm Life cycle photos of the salt marsh moth Estigmene acrea]
- [http://www.ukmoths.force9.co.uk/ UK Moths]
- [http://www.uklepidoptera.co.uk/ UK Lepidoptera]
- [http://www.leps.nl/ Butterflies and Moths of the Netherlands]
-
Category:Pollination
ja:ガ
Larva
A larva (Latin; plural larvae) is a juvenile form of animal with indirect development, undergoing metamorphosis (for example, insects or amphibians).
The larva can look completely different from the adult form, for example, a caterpillar differs from a butterfly. Larvae often have special (larval) organs which do not occur in the adult form. The larvae of some species can become pubescent and not further develop into the adult form (for example, in some newts). This is called neoteny.
It is a misunderstanding that the larval form always reflects the groups evolutionary history. It could be the case, but often the larval stage has evolved secondarily, like in insects. In these cases the larval form might differ more from the group's common origin than the adult form. The primary larval form it does not necessarily show how an animal's ancestors looked like, since this stage often has evolved in its own direction just as the adult form has.
Names of various kinds of larvae:
Category:Developmental biology
simple:Larva
Lepidoptera
Butterflies
- Hesperioidea
- Papilionoidea
Moths
- Micropterigoidea
- Heterobathmioidea
- Eriocranioidea
- Acanthopteroctetoidea
- Lophocoronoidea
- Neopseustoidea
- Mnesarchaeoidea
- Hepialoidea
- Nepticuloidea
- Incurvarioidea
- Palaephatoidea
- Tischeriodea
- Simaethistoidea
- Tineoidea
- Gracillarioidea
- Yponomeutoidea
- Gelechioidea
- Zygaenoidea
- Sesioidea
- Cossoidea
- Tortricoidea
- Choreutoida
- Urodoidea
- Galacticoidea
- Schreckensteinioidea
- Epermenioidea
- Pterophoroidea
- Aluctoidea
- Immoidea
- Axioidea
- Hyblaeoidea
- Thyridoidea
- Whalleyanoidea
- Pyraloidea
- Mimallonoidea
- Lasiocampoidea
- Geometroidea
- Drepanoidea
- Bombycoidea
- Calliduloidae
- Hedyloidea
- Noctuoidea
About 130 - see text
The Lepidoptera is the second largest order of insects comprising butterflies, skippers, and moths. Lepidopterans (members of this order) go through a four-stage life cycle of egg–larva/caterpillar–pupa/chrysalis–imago/adult. Adults have two pairs of membranous wings covered with scales, and mouth parts adapted for sucking.
The order comprises more than 180,000 species in 127 families and 46 superfamilies. It is second only to the Coleoptera (the beetles). The name is from Greek "scaly-wing" (lepido-pteron).
There are currently six species that are listed as critically endangered, 36 are endangered, and a further 116 are vulnerable.
See also metamorphosis (biology) and difference between a butterfly and a moth.
Families of Lepidoptera
difference between a butterfly and a moth
There are thought to be about 130 families in this order, but opinions frequently change among lepidoperists as to which these are. The treatment here is that adopted for the Natural History Museum database [http://www.nhm.ac.uk/entomology/butmoth/]. Generally, this uses the families included in the series of reviews published as Kristensen (1999), but for the superfamily Gelechoidea, it retains the system of Nye & Fletcher (1991) rather than the contentious treatment of Hodges in Kristensen. Also, the Riodinidae are retained as a family in anticipation of a publication by Lamas et al which will reinstate this as a full family. (In Kristensen they are treated as a subfamily of the Lycaenidae.) The list also shows where other authors in the fairly recent past have treated groups as belonging in other families. The actual number of families listed here is 126.
Lepidoptera is divided into several suborders, the largest being Ditrysia. Several other classifications of Lepidoptera families are commonly used. Butterflies families are collectively known as Rhopalocera (club-horned), while moth families are collectively known as Heterocera (varied-horned). This, however, is a popular, not scientific division (see: Difference between a butterfly and a moth). Lepidoperists also group families by size of species members: microlepidoptera for small species, and macrolepidoptera for large species.
References
- Kristensen, N.P. (Ed.). 1999. Lepidoptera, Moths and Butterflies. Volume 1: Evolution, Systematics, and Biogeography. Handbuch der Zoologie. Eine Naturgeschichte der Stämme des Tierreiches / Handbook of Zoology. A Natural History of the phyla of the Animal Kingdom. Band / Volume IV Arthropoda: Insecta Teilband / Part 35: 491 pp. Walter de Gruyter, Berlin, New York.
- Nye, I.W.B. & Fletcher, D.S. 1991. Generic Names of Moths of the World. Volume 6: xxix + 368 pp. Trustees of the British Museum (Natural History), London.
- Firefly Encyclopedia of Insects and Spiders, edited by Christopher O'Toole, ISBN 1-55297-612-2, 2002
- [http://www.leps.it/ Moths and Butterflies of Europe and North Africa]
- [http://www.ukmoths.force9.co.uk/ British Butterflies and Moths]
- [http://home.hccnet.nl/bernard.fransen/0testsite/0testsite/ Photography of European Butterflies and Moths]
- [http://www.leps.nl/ Butterflies and Moths in the Netherlands]
External link
- [http://alpha.furman.edu/~snyder/snyder/lep/faq1.htm The Butterfly and Moth FAQ Page]
- [http://www.goliathus.cz/en/museum-lepidoptera-6.html Lepidoptera] in [http://www.goliathus.cz/en/museum-homepage-0.html online insect museum]
List of currently accepted families
List of relegated families
The following groups have been ranked as families in the fairly recent past, and the family names are still likely to be met with in books and on the internet. This list shows where the supposed families are now classified.
-
ko:나비목
ja:チョウ目
Hummingbird Hawk-moth
larger view
The Hummingbird Hawk-moth (Macroglossum stellatarum) is a species of hawk moth with a long proboscis, and is capable of hovering in place, making an audible humming noise. These two features make it look remarkably like a hummingbird when it feeds on flowers. The forewings are brown and the hindwings are orange. The wingspan is 50-58 mm.
Adults may be encountered at any time of the year, especially in the south of the range and two or more broods are produced each year. They fly during the day, especially in bright sunshine. The larva is green with two stripes along the sides and the horn at the rear end typical of sphingids. It usually feeds on bedstraws and madders but has been recorded on other plants including Aster, Centaurea, Petunia, Phlox and various thistles.
The species is distributed throughout the Northern Hemisphere but is resident only in warmer climates. It is strongly migratory and can be found virtually anywhere in the hemisphere in the summer. However it rarely survives the winter in northern latitudes (eg north of the Alps in Europe).
Category:Sphingidae
EurybiaIn Greek mythology, Eurybia was married to the titan Crius and gave birth to three known offspring Astraios, Perses, and Pallas. She was a minor Sea Goddess under the dominion of Poseidon. Her parents were Pontos and Gaia.
Eurybia is mentioned, briefly, by Hesiod in his epic Theogony, and by Apollodorus in his play The Library.
Thespius's daughter is also named Eurybia.
----
Eurybia is also the name for a North American subgenus of the flower genus Aster.
See Eurybia (genus).
category:Greek goddesses
Ionactis
See text.
Ionactis, or the Stiff-leaved Asters, is small genus of five species, belonging to the sunflower family (Asteraceae)
The generic name, Ionactis, is derived from two Greek words meaning "violet rays."
This aster-like plants are endemic in North America. Four species occur on dry clearings or rocky slopes at mid to high elevations in the Rocky Mountains and the Cascade Mountains. One species, Ionactis linariifolia, occurs in most of eastern North America.
Ionactis was classified as a separate genus by Edward Lee Greene in 1897 with the species Ionactis linariifolia, which had been classified by Carolus Linnaeus as Aster linariifolius. Three other species were formerly classified under Aster, Chaetopappa or Ionactis. The species of Aster (in a strict sense) are now restricted to Eurasia.
The Stiff-leaved Asters are perennial herbs with numerous green stems, about 2,5 cm long (rarely 10cm), usually in a tussock. The spatulate leaves are small, stiff, sharply ascending and thick about the stem. The upper leaves are much smaller than the lower. Yellow-orange resin droplets form on the leaves of the Red Rock Canyon Aster (Ionactis caelestis).
The involucral phyllaries (bracts under the flower head) are narrow and overlapping. They have, along the midrib, a narrow zone containing chlorophyll. The silky-hairy, fusiform achenes form a crown with a double pappus in two series, the inner one with long, barbellate bristles, the outher one with short bristles or minute scales.
The small flower heads grow solitary or sometimes in a cluster at the end of the stems. The 10–24 fertile ray florets are nearly white, blue to pink, lavender, purple or blue violet. The sterile disc florets are yellowish. The peduncles are nearly naked.
They have a chromosome base number of x = 9.
Species
- Ionactis alpina : Lava Aster, Alpine Ionactis.
- Ionactis caelestis : Red Rock Canyon Aster, described in 1992 by P. J. Leary and Guy L. Nesom.
- Ionactis elegans : Sierra Blanca Cliff Daisy.
- Ionactis linariifolia : Flaxleaf Whitetop Aster, Grass-leaf Aster, Narrow-leaved White-topped Aster.
- Ionactis stenomeres : Rocky Mountain Aster.
References
- Nesom, G. 1994. - Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the new world species. Phytologia 77:141-297.
- Xiang, C. & J.C. Semple. 1996. - Molecular systematic study of Aster sensu lato and related genera (Asteraceae: Astereae) based on choroplast DNA restriction site analyses and mainly North American taxa. Pp. 393-423, in D.J.N. Hind & H.J. Beentje (eds.), Compositae: systematics. Proc. Intern.
Category:Asteraceae
Aster novae-angliae
Symphyotrichum novae-angliae
New England Aster (Symphyotrichum novae-angliae, Synonym: Aster novae-angliae) is found throughout northeastern, central and northwestern North America.
This plant grows up to 2 metres with stout, hairy stem. Flower heads are 2.5 - 5 cm wide.
Leaves are clasping, lanceolate, and generally entire. 2n=10
This plant's habitat includes damp meadows, fields, and shores.
Flower
Category:Asteraceae AmmoniakvandEn vandig opløsning af ammoniak i vand kaldes ammoniakvand (NH4+OH) eller salmiakspiritus. Bruges til rensning.
Den sidstnævnte betegnelse er gængs, men misvisende, da dette produkt hverken indeholder salmiak eller spiritus. (Sammenlign Børnejod.)
Ammoniakvand er en svag base.
Se også
- Rengøring
- Ammonium
- Ammoniak
statystyki prace magisterskie Kwiaciarnia d Hotel Genoa wegetarianizm
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