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Flowering Dogwood

Flowering Dogwood

The Flowering Dogwood (Cornus florida or Benthamidia florida) is a showy small tree native to eastern and southeastern North America, where it is also one of the most popular of all small ornamental flowering trees. Like most dogwoods, it has opposite, simple leaves. The tree is extremely showy when in flower, but what people assume to be the flowers are actually showy bracts below the cluster of inconspicuous yellow-green flowers. bract] While most of the wild trees are white-flowering, some selected cultivars of this tree also have pink flowers, some even almost a true red. They typically flower in early April in the southern part of their range, to late April or early May in northern and high altitude areas. The similar Kousa Dogwood (Cornus kousa), native to Asia, flowers about a month later. Like all dogwoods, Flowering Dogwood produces clusters of green berries which ripen to a bright red in the autumn; they are eaten by birds which distribute the seeds. The berries are edible, though lacking in any interesting flavor. The leaves are opposite, simple acute oval, apparently entire (actually very finely toothed, under a lens), and 6-13 cm long and 4-6 cm broad; they turn a rich red-brown in autumn. Flowering Dogwood does best horticulturally when it has shade from the west but has good morning sun. It does not do well when exposed to intense heat sources such as adjacent parking lots or air conditioning compressors. compressors It is very susceptible to dogwood anthracnose, a disease caused by the fungus Discula destructiva. This has killed many wild stocks of Flowering Dogwood; domestic landscape plantings have often been less badly affected because better air circulation and less humid conditions discourages the fungus, but losses still occur frequently. The Kousa Dogwood is resistant to this disease. Image:Benthamidia florida berry.jpg|Berries Image:Benthamidia florida autumn.jpg|Tree shape, Autumn Dogwood, Flowering ja:ハナミズキ

Tree

, the tallest tree species on earth]] A tree can be defined as a large, perennial, woody plant. Though there is no set definition regarding minimum size, the term generally applies to plants at least 6 m (20 ft) high at maturity and, more importantly, having secondary branches supported on a single main stem or trunk (see shrub for comparison). Compared with most other plant forms, trees are long-lived. A few species of trees grow to 100 m tall, and some can live for several thousand years. Trees are important components of the natural landscape and significant elements in landscaping, and in agriculture supplying orchard crops (such as apples). Trees also play an important role in many of the world's mythologies (see Tree (mythology)).

Classifications

Tree (mythology)]] A tree is a plant form and trees occur in many different orders and families of plants. Trees thus show a wide variety of growth form, leaf type and shape, bark characteristics, reproductive structures, etc. The earliest trees were tree ferns and horsetails, which grew in vast forests in the Carboniferous Period; tree ferns still survive, but the only surviving horsetails are not of tree form. Later, in the Triassic Period, conifers, ginkgos, cycads and other gymnosperms appeared, and subsequently flowering plants in the Cretaceous Period. Most species of trees today are flowering plants and conifers. The listing below gives examples of many well-known trees and how they are typically classified. A small group of trees growing together is called a grove or copse, and a landscape covered by a dense growth of trees is called a forest. Several biotopes are defined largely by the trees that inhabit them; examples are rainforest and taiga (see ecozones). A landscape of trees scattered or spaced across grassland (usually grazed or burned over periodically) is called a savanna.

Morphology

The basic parts of a tree are the roots, trunk(s), branches, twigs and leaves. Tree stems consist mainly of support and transport tissues (xylem and phloem). Wood consists of xylem cells, and bark is made of phloem and other tissues external to the vascular cambium. Trees may be broadly grouped into exogenous and endogenous trees according to the way in which their stem diameter increases. Exogenous trees, which comprise the great majority of modern trees (all conifers, and all broadleaf trees), grow by the addition of new wood outwards, immediately under the bark. Endogenous trees, mainly in the monocotyledons (e.g. palms), grow by addition of new material inwards. As an exogenous tree grows, it creates growth rings. In temperate climates, these are commonly visible due to changes in the rate of growth with temperature variation over an annual cycle. These rings can be counted to determine the age of the tree, and used to date cores or even wood taken from trees in the past; this practice is known as the science of dendrochronology. In some tropical regions with constant year-round climate, growth is continuous and distinct rings are not formed, so age determination is impossible. Age determination is also impossible in endogenous trees. dendrochronology, Chile]] The roots of a tree are generally embedded in earth, providing anchorage for the above-ground biomass and absorbing water and nutrients from the soil. Above ground, the trunk gives height to the leaf-bearing branches, aiding in competition with other plant species for sunlight. In many trees, the arrangement of the branches optimizes exposure of the leaves to sunlight. Not all trees have all the plant organs or parts mentioned above. For example, most palm trees are not branched, the saguaro cactus of North America has no functional leaves, tree ferns do not produce bark, etc. Based on their general shape and size, all of these are nonetheless generally regarded as trees. Indeed, sometimes size is the more important consideration. A plant form that is similar to a tree, but generally having smaller, multiple trunks and/or branches that arise near the ground, is called a shrub. However, no sharp differentiation between shrubs and trees is possible. Given their small size, bonsai plants would not technically be 'trees', but one should not confuse reference to the form of a species with the size or shape of individual specimens. A spruce seedling does not fit the definition of a tree, but all spruces are trees. Bamboos by contrast, do show most of the characteristics of trees, yet are rarely called trees.

Champion trees

The world's champion trees can be considered on several factors; height, trunk diameter or girth, total size, and age. It is significant that in each case, the top position is always held by a conifer, though a different species in each case; in most measures, the second to fourth places are also held by conifers. ;Tallest trees The heights of the tallest trees in the world have been the subject of considerable dispute and much (often wild) exaggeration. Modern verified measurement with laser rangefinders combined with tape drop measurements made by tree climbers, carried out by the [http://www.uark.edu/misc/ents/home.htm U.S. Eastern Native Tree Society] has shown that most older measuring methods and measurements are unreliable, often producing exaggerations of 5% to 15% above the real height. Historical claims of trees of 114 m, 117 m, 130 m, and even 150 m, are now largely disregarded as unreliable, fantasy or outright fraud. The following are now accepted as the top five tallest reliably measured species: # Coast Redwood Sequoia sempervirens: 112.83 m, Humboldt Redwoods State Park, California ([http://www.conifers.org/cu/se/index.htm Gymnosperm Database]) # Coast Douglas-fir Pseudotsuga menziesii: 100.3 m, Brummit Creek, Coos County, Oregon ([http://www.conifers.org/pi/ps/menziesii2.htm Gymnosperm Database]) # Sitka Spruce Picea sitchensis: 96.7 m, Prairie Creek Redwoods State Park, California ([http://www.conifers.org/pi/pic/sitchensis.htm Gymnosperm Database]) # Giant Sequoia Sequoiadendron giganteum: 93.6 m, Redwood Mountain Grove, California ([http://www.conifers.org/cu/se2/index.htm Gymnosperm Database]) # Australian Mountain-ash Eucalyptus regnans: 92.0 m, Styx Valley, Tasmania ([http://www.forestrytas.com.au/forestrytas/tasfor/tasforests_12/tasfor_12_09.pdf Forestry Tasmania] [pdf file]) ;Stoutest trees The girth (circumference) of a tree is – or at least should be – much easier to measure than the height, as it is a simple matter of stretching a tape round the trunk, and pulling it taut to find the circumference. Despite this, U.K. tree author Alan Mitchell made the following comment about measurements of yew trees in the British Isles: :"The aberrations of past measurements of yews are beyond belief. For example, the tree at Tisbury has a well-defined, clean, if irregular bole at least 1.5 m long. It has been found to have a girth which has dilated and shrunk in the following way: 11.28 m (1834 Loudon), 9.3 m (1892 Lowe), 10.67 m (1903 Elwes and Henry), 9.0 m (1924 E. Swanton), 9.45 m (1959 Mitchell) .... Earlier measurements have therefore been omitted". As a general standard, tree girth is taken at 'breast height'; this is defined differently in different situations, with most foresters measuring girth at 1.3 m above ground, while ornamental tree measurers usually measure at 1.5 m above ground; in most cases this makes little difference to the measured girth. On sloping ground, the "above ground" reference point is usually taken as the highest point on the ground touching the trunk, but some use the average between the highest and lowest points of ground. Some of the inflated old measurements may have been taken at ground level. Some past exaggerated measurements also result from measuring the complete next-to-bark measurement, pushing the tape in and out over every crevice and buttress. Modern trends are to cite the tree's diameter rather than the circumference; this is obtained by dividing the measured circumference by π; it assumes the trunk is circular in cross-section (an oval or irregular cross-section would result in a mean diameter slightly greater than the assumed circle). This is cited as dbh (diameter at breast height) in tree literature. A further problem with measuring baobabs Adansonia is that these trees store large amounts of water in the very soft wood in their trunks. This leads to marked variation in their girth over the year, swelling to a maximum at the end of the rainy season, minimum at the end of the dry season. Although baobabs have some of the highest girth measurements of any trees, no accurate measurements are currently available, but probably do not exceed 10-11 m diameter. The stoutest species in diameter, excluding baobabs, are: # Montezuma Cypress Taxodium mucronatum: 11.42 m, Árbol del Tule, Santa Maria del Tule, Oaxaca, Mexico (A. F. Mitchell, International Dendrology Society Year Book 1983: 93, 1984). # Giant Sequoia Sequoiadendron giganteum: 8.85 m, General Grant tree, Grant Grove, California ([http://www.conifers.org/cu/se2/index.htm Gymnosperm Database]) # Coast Redwood Sequoia sempervirens: 7.44 m, Prairie Creek Redwoods State Park, California ([http://www.conifers.org/cu/se/index.htm Gymnosperm Database]) ;Largest trees The largest trees in total volume are those which are both tall and of large diameter, and in particular, which hold a large diameter high up the trunk. Measurement is very complex, particularly if branch volume is to be included as well as the trunk volume, so measurements have only been made for a small number of trees, and generally only for the trunk. No attempt has ever been made to include root volume. The top four species measured so far are ([http://www.conifers.org/topics/biggest.htm Gymnosperm Database]): # Giant Sequoia Sequoiadendron giganteum: 1489 m³, General Sherman tree # Coast Redwood Sequoia sempervirens: 1045 m³, Del Norte Titan tree # Western Redcedar Thuja plicata: 500 m³, Quinault Lake Redcedar # Kauri Agathis australis: 400 m³, Tane Mahuta tree (total volume, including branches, 516.7 m³)
However, the Alerce Fitzroya cupressoides, as yet un-measured, may well slot in at third or fourth place, and Montezuma Cypress Taxodium mucronatum is also likely to be high in the list. The largest angiosperm tree is a Australian Mountain-ash, the 'El Grande' tree of about 380 m³ in Tasmania. ;Oldest trees The oldest trees are determined by growth ring counts in cores taken from the edge to the centre of the tree or from entire cross-sections. Accurate determination is only possible for trees which produce growth rings, generally those which occur in seasonal climates; trees in uniform non-seasonal tropical climates grow continuously and do not have distinct growth rings. It is also only possible for trees which are solid to the centre of the tree; many very old trees become hollow as the dead heartwood decays away. For some of these species, age estimates have been made on the basis of extrapolating current growth rates, but the results are usually little better than guesswork or wild speculation. The verified oldest measured ages are ([http://www.conifers.org/topics/oldest.htm Gymnosperm Database]): # Great Basin Bristlecone Pine Pinus longaeva: 4844 years # Alerce Fitzroya cupressoides: 3622 years # Giant Sequoia Sequoia sempervirens: 3266 years # Huon-pine Lagarostrobos franklinii: 2500 years # Rocky Mountains Bristlecone Pine Pinus aristata: 2435 years Other species suspected of reaching exceptional age include European Yew Taxus baccata (probably over 3000 years) and Western Redcedar Thuja plicata. The oldest verified age for an angiosperm tree is 2293 years for the Sri Maha Bodhi Sacred Fig (Ficus religiosa) planted in 288 BC at Anuradhapura, Sri Lanka; this is also the oldest human-planted tree with a known planting date.

Major tree genera

Flowering plants (Magnoliophyta; angiosperms)

Dicotyledons (Magnoliopsida; broadleaf or hardwood trees)

- Anacardiaceae (Cashew family)
- Cashew, Anacardium occidentale
- Mango, Mangifera indica
- Pistachio, Pistacia vera
- Sumac, Rhus species
- Lacquer tree, Toxicodendron verniciflua
- Annonaceae (Custard apple family)
- Cherimoya Annona cherimola
- Custard apple Annona reticulata
- Pawpaw Asimina triloba
- Soursop Annona muricata
- Apocynaceae (Dogbane family)
- Pachypodium Pachypodium species
- Aquifoliaceae (Holly family)
- Holly, Ilex species
- Araliaceae (Ivy family)
- Kalopanax, Kalopanax pictus Kalopanax tree (background) in fall]]
- Betulaceae (Birch family)
- Alder, Alnus species
- Birch, Betula species
- Hornbeam, Carpinus species
- Hazel, Corylus species
- Bignoniaceae (family)
- Catalpa, Catalpa species
- Cactaceae (Cactus family)
- Saguaro, Carnegiea gigantea
- Cannabaceae (Cannabis family)
- Hackberry, Celtis species
- Cornaceae (Dogwood family)
- Dogwood, Cornus species
- Dipterocarpaceae family
- Garjan Dipterocarpus species
- Sal Shorea species
- Ericaceae (Heath family)
- Arbutus, Arbutus species
- Eucommiaceae (Eucommia family)
- Eucommia Eucommia ulmoides
- Fabaceae (Pea family)
- Acacia, Acacia species
- Honey locust, Gleditsia triacanthos
- Black locust, Robinia pseudoacacia
- Laburnum, Laburnum species
- Pau Brasil, Brazilwood, Caesalpinia echinata
- Fagaceae (Beech family )
- Chestnut, Castanea species
- Beech, Fagus species
- Southern beech, Nothofagus species
- Tanoak, Lithocarpus densiflorus
- Oak, Quercus species
- Fouquieriaceae (Boojum family)
- Boojum, Fouquieria columnaris
- Hamamelidaceae (Witch-hazel family)
- Sweetgum, Liquidambar species
- Persian Ironwood, Parrotia persica
- Juglandaceae (Walnut family)
- Walnut, Juglans species
- Hickory, Carya species
- Wingnut, Pterocarya species
- Lauraceae (Laurel family)
- Cinnamon Cinnamomum zeylanicum
- Bay Laurel Laurus nobilis
- Avocado Persea americana
- Lecythidaceae (Paradise nut family)
- Brazil Nut Bertholletia excelsa
- Lythraceae Loosestrife family
- Crape-myrtle Lagerstroemia species
- Magnoliaceae (Magnolia family)
- Tulip tree, Liriodendron species
- Magnolia, Magnolia species
- Malvaceae (Mallow family; including Tiliaceae and Bombacaceae) Bombacaceae
- Baobab, Adansonia species
- Silk-cotton tree, Bombax species
- Bottletrees, Brachychiton species
- Kapok, Ceiba pentandra
- Durian, Durio zibethinus
- Balsa, Ochroma lagopus
- Cacao (cocoa), Theobroma cacao
- Linden (Basswood, Lime), Tilia species
- Meliaceae (Mahogany family)
- Neem, Azadirachta indica
- Bead tree, Melia azedarach
- Mahogany, Swietenia mahagoni
- Moraceae (Mulberry family)
- Fig, Ficus species
- Mulberry, Morus species
- Myristicaceae (Nutmeg family)
- Nutmeg, Mysristica fragrans
- Myrtaceae (Myrtle family)
- Eucalyptus, Eucalyptus species
- Myrtle, Myrtus species
- Guava, Psidium guajavaGuava in flower]]
- Nyssaceae (Tupelo family; sometimes included in Cornaceae)
- Tupelo, Nyssa species
- Dove tree, Davidia involucrata
- Oleaceae (Olive family)
- Olive, Olea europaea
- Ash, Fraxinus species
- Paulowniaceae (Paulownia family)
- Foxglove Tree, Paulownia species
- Platanaceae (Plane family)
- Plane, Platanus species
- Rhizophoraceae (Mangrove family)
- Red Mangrove, Rhizophora mangle
- Rosaceae (Rose family)
- Rowans, Whitebeams, Service Trees Sorbus species
- Hawthorn, Crataegus species
- Pear, Pyrus species
- Apple, Malus species
- Almond, Prunus dulcis
- Peach, Prunus persica
- Plum, Prunus domestica
- Cherry, Prunus species
- Rubiaceae (Bedstraw family)
- Coffee, Coffea species
- Rutaceae (Rue family)
- Citrus, Citrus species
- Cork-tree, Phellodendron species
- Euodia, Tetradium species
- Salicaceae (Willow family)
- Aspen, Populus species
- Poplar, Populus species
- Willow, Salix species Willow
- Sapindaceae (including Aceraceae, Hippocastanaceae) (Soapberry family)
- Maple, Acer species
- Buckeye, Horse-chestnut, Aesculus species
- Mexican Buckeye, Ungnadia speciosa
- Lychee, Litchi sinensis
- Golden rain tree, Koelreuteria paniculata
- Sapotaceae (Sapodilla family)
- Gutta-percha, Palaquium species
- Tambalacoque, or "dodo tree", Sideroxylon grandiflorum, previously Calvaria major
- Simaroubaceae family
- Tree of heaven, Ailanthus species
- Theaceae (Camellia family)
- Gordonia, Gordonia species
- Stuartia, Stuartia species
- Thymelaeaceae (Thymelaea family)
- Ramin, Gonystylus species
- Ulmaceae (Elm family)
- Elm, Ulmus species
- Zelkova, Zelkova species
- Verbenaceae family
- Teak, Tectona species

Monocotyledons (Liliopsida)

Monocotyledon
- Agavaceae (Agave family)
- Cabbage tree, Cordyline australis
- Dragon tree, Dracaena draco
- Joshua tree, Yucca brevifolia
- Arecaceae (Palmae) (Palm family)
- Areca Nut, Areca catechu
- Coconut Cocos nucifera
- Date Palm, Phoenix dactylifera
- Chusan Palm, Trachycarpus fortunei
- Poaceae (grass family)
- Bamboos Poaceae subfamily Bambusoideae
- Note that banana 'trees' are not actually trees; they are not woody nor is the stalk perennial.

Conifers (Pinophyta; softwood trees)

- Araucariaceae (Araucaria family)
- Araucaria, Araucaria species
- Kauri, Agathis species
- Cupressaceae (Cypress family)
- Cypress, Cupressus species
- Cypress, Chamaecyparis species
- Juniper, Juniperus species
- Alerce or Patagonian cypress, Fitzroya cupressoides
- Sugi, Cryptomeria japonica
- Coast Redwood, Sequoia sempervirens
- Giant Sequoia, Sequoiadendron giganteum
- Dawn Redwood, Metasequoia glyptostroboides
- Bald Cypress, Taxodium distichum
- Pinaceae (Pine family)
- White pine, Pinus species
- Pinyon pine, Pinus species
- Pine, Pinus species
- Spruce, Picea species
- Larch, Larix species
- Douglas-fir, Pseudotsuga species
- Fir, Abies species
- Cedar, Cedrus species
- Podocarpaceae (Yellowwood family)
- African Yellowwood, Afrocarpus falcatus
- Totara, Podocarpus totara
- Sciadopityaceae
- Kusamaki, Sciadopitys species
- Taxaceae (Yew family)
- Yew, Taxus species

Ginkgos (Ginkgophyta)

- Ginkgoaceae (Ginkgo family)
- Ginkgo, Ginkgo biloba

Cycads (Cycadophyta)

- Cycadaceae family
- Ngathu cycad, Cycas angulata
- Zamiaceae family
- Wunu cycad, Lepidozamia hopei

Ferns (Pterophyta)

- Cyatheaceae and Dicksoniaceae families
- Tree ferns, Cyathea, Alsophila, Dicksonia (not a monophyletic group)

Life stages

The life cycles of trees, especially conifers, are divided into the following stages in forestry for survey and documentation purposes: # Seed # Seedling: the above ground part of the embryo that sprout from the seed # Sapling: After the seedling reaches 1m tall, and until it reaches 7cm in stem diameter # Pole: young trees from 7-30cm diameter # Mature tree: over 30cm diameter, reproductive years begin # Old tree: dominate old growth forest; height growth slows greatly, with majority of productivity in seed production # Overmature: dieback and decay become common # Snag: standing dead wood # Log/debris: fallen dead wood Tree diameters are measured at height of between 1.3-1.5m above the highest point on the ground at its base. The 7cm diameter definition is economically based, from the smallest saleable stem size (for paper production, etc), and the 30cm diameter is the smallest base diameter for sawlogs. Each stage may be uniquely perceptive to different pathogens and suitable for especially adapted arboreal animals.

External links

- [http://www.globaltrees.org/default.asp GLOBAL TREES .org] Campaigning to save the world's most threatened trees
- [http://www.fssca.net/romero/ Romero Memorial Tree Project] Plant a tree in El Salvador

Bibliography

- Pakenham, T. (2002). Remarkable Trees of the World. ISBN 0297843001
- Pakenham, T. (1996). Meetings with Remarkable Trees. ISBN 0297832557 Category:Plants
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- Category:Botany Category: plant morphology ms:Pokok ja:木 simple:Tree th:ต้นไม้

Indigenous

The word indigenous is an adjective derived from the Latin word indigena, meaning native, belonging to, aboriginal; and has several applications:
- Indigenous peoples, communities and cultures native or indigenous to a territory;
- Indigenous (band), a Native American blues-rock band;
- In biology, indigenous means native to a place or biota, in contrast to any one of several terms meaning not native to a place (nonnative, alien, adventive, introduced) and differentiated from endemic. A species that is endemic is unique to that place, found naturally nowhere else. A species that is indigenous is native, but not unique in the sense that it is also native to other locations as well. Thus, a species that is native to California but found naturally in Oregon and Washington as well (native to the West Coast of the United States) is indigenous to California. A species found only in the British Isles is endemic to those islands.

Dogwood

Cornus
Benthamidia
Swida The Dogwoods comprise a group of 30-50 species of deciduous woody plants (shrubs and trees) in the family Cornaceae, divided into one to nine genera or subgenera (depending on botanical interpretation). Four subgenera are enumerated here.
- Flower clusters semi-showy, usually white or yellow, in cymes without large showy bracts, fruit red, blue or white:
- (Sub)genus Cornus. Cornels; four species of shrubs or small trees; flower clusters with a deciduous involucre.
- Cornus chinensis (Chinese Cornel). China.
- Cornus mas (European Cornel or Cornelian-cherry). Mediterranean.
- Cornus officinalis (Japanese Cornel). Japan.
- Cornus sessilis (Blackfruit Cornel). California.
- (Sub)genus Swida. Dogwoods; about 20-30 species of shrubs; flower clusters without an involucre.
- Cornus alba (Swida alba; Siberian Dogwood). Siberia and northern China.
- Cornus alternifolia (Swida alternifolia; Pagoda Dogwood or Alternate-leaf Dogwood). Eastern North America north to extreme southeast Canada.
- Cornus amomum (Swida amomum; Silky Dogwood). Eastern U.S. east of the Great Plains except for deep south, and extreme southeast Canada.
- Cornus asperifolia (Swida asperifolia; Rough-leaf Dogwood).
- Cornus austrosinensis (Swida austrosinensis; South China Dogwood). East Asia.
- Cornus bretschneideri (Swida bretschneideri; Bretschneider's Dogwood). Northern China.
- Cornus controversa (Swida controversa; Table Dogwood). East Asia.
- Cornus coreana (Swida coreana; Korean Dogwood). Northeast Asia.
- Cornus drummondii (Swida drummondii; Roughleaf Dogwood). U.S. between the Appalachian belt and the Great Plains, and southern Ontario.
- Cornus glabrata (Swida glabrata; Brown Dogwood or Smooth Dogwood). Western North America.
- Cornus hemsleyi (Swida hemsleyi; Hemsley's Dogwood). Southwest China.
- Cornus koehneana (Swida koehneana; Koehne's Dogwood). Southwest China.
- Cornus macrophylla (Swida macrophylla; Large-leafed Dogwood). East Asia.
- Cornus obliqua (Swida obliqua; Pale Dogwood). Eastern North America.
- Cornus paucinervis (Swida paucinervis). China.
- Cornus racemosa (Swida racemosa; Northern Swamp Dogwood or Gray Dogwood). Extreme southeast Canada and northeast U.S.
- Cornus rugosa (Swida rugosa; Round-leaf Dogwood). Southeast Canada and extreme northeast U.S.
- Cornus sanguinea (Swida sanguinea; Common Dogwood). Europe.
- Cornus sericea (C. stolonifera; Swida stolonifera; Red Osier Dogwood). Northern North America.
- Cornus stricta (Swida stricta; Southern Swamp Dogwood). Southeast U.S.
- Cornus walteri (Swida walteri; Walter's Dogwood). Central China.
- Cornus wilsoniana (Swida wilsoniana; Wilson's Dogwood). Central China.
- Flower clusters inconspicuous, usually greenish, surrounded by large, showy petal-like bracts; fruit usually red:
- (Sub)genus Chamaepericlymenum. Dwarf cornels; two species of creeping subshrubs growing from woody stolons.
- Cornus canadensis (Chamaepericlymenum canadense; Canadian Dwarf Cornel or Bunchberry) Northern North America.
- Cornus suecica (Chamaepericlymenum suecicum; Eurasian Dwarf Cornel). Northern Eurasia, locally in extreme northeast and northwest North America.
- Cornus x unalaschkensis (hybrid C. canadensis x C. suecica). Aleutian Islands, Greenland, Labrador.
- (Sub)genus Benthamidia (syn. subgenus Dendrobenthamia, subgenus Cynoxylon). Flowering dogwoods; five species of trees.
- Cornus capitata (Benthamidia capitata; Himalayan Flowering Dogwood). Himalaya.
- Cornus florida (Benthamidia florida; Flowering Dogwood). U.S. east of the Great Plains, north to southern Ontario.
- Cornus hongkongensis (Benthamidia hongkongensis; Hongkong Dogwood). Southern China, Laos, Vietnam.
- Cornus kousa (Benthamidia kousa; Kousa Dogwood). Japan and (as subsp. chinensis) central and northern China.
- Cornus nuttallii (Benthamidia nuttallii; Pacific Dogwood). Western North America from British Columbia to California.
- Cornus urbaniana (Benthamidia urbaniana; Mexican Flowering Dogwood). Mexico. Most species have opposite leaves, but alternate in a few. The fruit of all species is a drupe with one or two seeds. Flowers have four parts. Many species in subgenus Swida are stoloniferous shrubs, growing along waterways. Several of these are used for naturalizing landscape plantings, especially the species with bright red or bright yellow stems. Most of the species in subgenus Benthamidia are small trees used as ornamental plants. The name 'dogwood' is a corruption of 'dagwood', from the use of the slender stems of very hard wood for making 'dags' (daggers, skewers). The wood was also highly prized for making the shuttles of looms, for tool handles, and other small items that required a very hard and strong wood. The fruit of several species in the subgenera Cornus and Benthamidia is edible, though without much flavour. The berries of those in subgenus Swida are mildly toxic to people, though readily eaten by birds. Dogwoods are used as food plants by the larvae of some Lepidoptera species including Emperor Moth, The Engrailed and Small Angle Shades. The dogwood is the provincial flower of the Canadian province of British Columbia. The dogwood (Cornus florida) is the state flower and the state tree for the Commonwealth of Virginia in the United States. The term dogwood winter may be used to describe a cold snap in spring. Popular legend has it that wood from the dogwood was used to construct the cross on which Christ was crucified. God had pity upon the tree, giving it white flowers similar to the cross. The reddish center of each flower symbolizes the blood of Christ. God transformed the once towered tree into one that is small with twisted, gnarled trunks so that could never be used for the purpose of building a cross again.

External links

- [http://hua.huh.harvard.edu/china/mss/volume14/Cornaceae-AGH_coauthoring.htm Asian dogwoods] Category:Cornales

Leaves

:This article is about the leaf, a plant organ. See Leaf (disambiguation) for other meanings. ---- In botany, a leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat (laminar) and thin, to expose the chloroplast containing cells (chlorenchyma tissue) to light over a broad area, and to allow light to penetrate fully into the tissues. Leaves are also the sites in most plants where respiration, transpiration, and guttation take place. Leaves can store food and water, and are modified in some plants for other purposes. The comparable structures of ferns are correctly referred to as fronds. frond frond frond

Leaf anatomy

A structurally complete leaf of an angiosperm consists of a petiole (leaf stem), a lamina (leaf blade), and stipules (small processes located to either side of the base of the petiole). The point at which the petiole attaches to the stem is called the leaf axil. Not every species produces leaves with all of these structural parts. In some species, paired stipules are not obvious or are absent altogether; a petiole may be absent; or the blade may not be laminar (flattened). The tremendous variety shown in leaf structure (anatomy) from species to species is presented in detail below under Leaf types, arrangements, and forms. A leaf is considered to be a plant organ, typically consisting of the following tissues: # An epidermis that covers the upper and lower surfaces # An interior chlorenchyma called the mesophyll # An arrangement of veins (the vascular tissue). stipule

Epidermis

The epidermis is the outer multi-layered group of cells covering the leaf. It forms the boundary between the plant and the external world. The epidermis serves several functions: protection against water loss, regulation of gas exchange, secretion of metabolic compounds, and (in some species) absorption of water. Most leaves show dorsoventral anatomy: the upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. The epidermis is usually transparent (epidermal cells lack chloroplasts) and coated on the outer side with a waxy cuticle that prevents water loss. The cuticle may be thinner on the lower epidermis than on the upper epidermis; and is thicker on leaves from dry climates as compared with those from wet climates. The epidermis tissue includes several differentiated cell types: epidermal cells, guard cells, subsidiary cells, and epidermal hairs (trichomes). The epidermal cells are the most numerous, largest, and least specialized. These are typically more elongated in the leaves of monocots than in those of dicots. The epidermis is covered with pores called stomata (sing., stoma), part of a stoma complex consisting of a pore surrounded on each side by chloroplast-containing guard cells, and two to four subsidiary cells that lack chloroplasts. The stoma complex regulates the exchange of gases and water vapor between the outside air and the interior of the leaf. Typically, the stomata are more numerous over the abaxial (lower) epidermis than the (adaxial) upper epidermis. Trichomes or hairs grow out from the epidermis in many species.

Mesophyll

Most of the interior of the leaf between the upper and lower layers of epidermis is a parenchyma (ground tissue) or chlorenchyma tissue called the mesophyll (= middle leaf). This "assimilation tissue" is the primary location of photosynthesis in the plant. The products of photosynthesis are called assimilates. In ferns and most flowering plants the mesophyll is divided into two layers:
- An upper palisade layer of tightly packed, vertically elongated cells, one to two cells thick, directly beneath the adaxial epidermis. Its cells contain many more chloroplasts than the spongy layer. These long cylindrical cells are regularly arranged in one to five rows. Cylindrical cells, with the chloroplasts close to the walls of the cell, can take optimal advantage of light. The slight separation of the cells provides maximum absorption of carbon dioxide. This separation must be minimal to afford capillary action for water distribution. In order to adapt to their different environment (such as sun or shade), plants had to adapt this structure to obtain optimal result. Sun leaves have a multi-layered palisade layer, while shade leaves or older leaves closer to the soil, are single-layered.
- Beneath the palisade layer is the spongy layer. The cells of the spongy layer are more rounded and not so tightly packed. There are large intercellular air spaces. These cells contain less chloroplasts than those of the palisade layer. The pores or stomata of the epidermis open into substomatal chambers, connecting to air spaces between the spongy layer cells. These two different layers of the mesophyll are absent in many aquatic and marsh plants. Even an epidermis and a mesophyll may be lacking. Instead for their gaseous exchanges they use a homogenous aerenchyma (thin-walled cells separated by large gas-filled spaces). Their stomata are situated at the upper surface. Leaves are normally green in color, which comes from chlorophyll found in plastids in the chlorenchyma cells. Plants that lack chlorophyll cannot photosynthesize. Leaves in temperate, boreal, and seasonally dry zones may be seasonally deciduous (falling off or dying for the inclement season). This mechanism to shed leaves is called abscission. After the leaf is shed, a leaf scar develops on the twig. In cold autumns they sometimes turn yellow, bright orange or red as various accessory pigments (carotenoids and anthocyanins) are revealed when the tree responds to cold and reduced sunlight by curtailing chlorophyll production.

Veins

The veins are the vascular tissue of the leaf and are located in the spongy layer of the mesophyll. They are typical examples of pattern formation through ramification. The veins are made up of:
- xylem, which brings water from the stem into the leaf.
- phloem, which usually moves sap out, the latter containing the glucose produced by photosynthesis in the leaf. The xylem typically lies over the phloem. Both are embedded in a dense parenchyma tissue (= ground tissue), called pith, with usually some structural collenchyma tissue present.

Leaf morphology

External leaf characteristics (such as shape, margin, hairs, etc.) are important for identifying plant species, and botanists have developed a rich terminology for describing leaf characteristics. phloem Leaves may be classified in many different ways, and the type is usually characteristic of a species, although some species produce more than one type of leaf. The terminology associated with describing leaf morphology is presented (with illustrations) at [http://wikibooks.org/wiki/Botany:_Leaves_(forms) Wikibooks].

Basic leaf types

- Ferns have fronds.
- Conifer leaves are typically needle-, awl-, or scale-shaped
- Angiosperm (flowering plant) leaves: the standard form includes stipules, petiole, and lamina.
- Microphyll leaves.
- Sheath leaves (type found in most grasses).
- Other specialized leaves.

Arrangement on the stem

As a stem grows, leaves tend to appear arranged around the stem in away that optimizes yield of light. In essence, leaves come off the stem in a spiral pattern, either clockwise or counterclockwise, with (depending upon the species) the same angle of divergence. There is a regularity in these angles and they follow the numbers in a Fibonacci series: 1/2, 2/3, 3/5, 5/8, 8/13, 13/21, 21/34, 34/55, 55/89. This series tends to a limit of 360° x 34/89 = 137,52 or 137° 30', an angle known mathematically as the 'golden angle'. In the series, the numerator gives the number of complete turns or gyres until the leaf arrives at the initial position. The denominator gives the number of leaves in the arrangement. This can be demonstrated by the following:
- alternate leaves have an angle of 180° (or 1/2)
- 120° (or 1/3) : three leaves in one circle
- 144° (or 2/5) : five leaves in two gyres
- 135° (or 3/8) : eight leaves in three gyres. The fact that an arrangement of anything in nature can be described by a mathematical formula is not in itself mysterious. Mathematics is the science of discovering numerical relationships and applying formulae to these relationships. The formulae themselves can provide clues to the underlying physiological processes that, in this case, determine where the next leaf bud will form in the elongating stem. However, we can more easily describe the arrangement of leaves using the following terms:
- Alternate — leaf attachments singular at nodes, and leaves alternate direction, to a greater or lesser degree, along the stem.
- Opposite — leaf attachments paired at each node; decussate if, as typical, each successive pair is rotated 90° going along the stem; or distichous if not rotated, but two-ranked (in the same plane).
- Whorled — three or more leaves attach at each point or node on the stem. As with opposite leaves, successive whorls may or may not be decussate, rotated by half the angle between the leaves in the whorl (i.e., successive whorls of three rotated 60°, whorls of four rotated 45°, etc). Note: opposite leaves may appear whorled near the tip of the stem.
- Rosulate — leaves form a rosette ( = a cluster of leaves growing in crowded circles from a common center). Fibonacci series

Divisions of the lamina (blade)

Two basic forms of leaves can be described considering the way the blade is divided. A simple leaf has an undivided blade. However, the leaf shape may be one of lobes, but the gaps between lobes do not reach to the main vein. A compound leaf has a fully subdivided blade, each leaflet of the blade separated along a main or secondary vein. Because each leaflet can appear to be a "simple leaf", it is important to recognize where the petiole occurs to identify a compound leaf. Compound leaves are a characteristic of some families of higher plants, such as the Fabaceae.
- Palmately compound leaves have the leaflets radiating from the end of the petiole, like fingers off the palm of a hand. There is no rachis, e.g. Cannabis (hemp) and Aesculus (buckeyes).
- Pinnately compound leaves have the leaflets arranged along the main or mid-vein (called a rachis in this case).
- odd pinnate: with a terminal leaflet, e.g. Fraxinus (ash).
- even pinnate: lacking a terminal leaflet, e.g. Swietenia (mahogany).
- Bipinnately compound leaves are twice divided: the leaflets are arranged along a secondary vein that is one of several branching off the rachis. Each leaflet is called a pinnule. The pinnules on one secondary vein are called pinna; e.g. Albizia (silk tree).
- trifoliate: a pinnate leaf with just three leaflets, e.g. Trifolium (clover), Laburnum (laburnum).
- pinnatifid: pinnately dissected to the midrib, but with the leaflets not entirely separate, e.g. some Sorbus (whitebeams). ;Characteristics of the petiole:
- Petiolated leaves have a petiole.
- In peltate leaves, the petiole attaches to the blade inside from the blade margin.
- Sessile or clasping leaves do not have a petiole. In sessile leaves the blade attaches directly to the stem. In clasping leaves, the blade partially or wholly surrounds the stem, giving the impression that the shoot grows through the leaf such as in Claytonia perfoliata of the purslane family (Portulacaceae). In some Acacia species, such as the Koa Tree (Acacia koa), the petioles are expanded or broadened and function like leaf blades; these are called phyllodes. There may or may not be normal pinnate leaves at the tip of the phyllode. ;Characteristics of the stipule
- A stipule, present on the leaves of many dicotyledons, is an appendage on each side at the base of the petiole, resembling a small leaf. They may be lasting and not be shed (a stipulate leaf, such as in roses and beans); or be shed as the leaf expands, leaving a stipule scar on the twig (an exstipulate leaf).
- The situation, arrangement, and structure of the stipules is called the stipulation.
- free
- adnate : fused to the petiole base
- ochreate : provided with ochrea, or sheath-formed stipules, e.g. rhubarb,
- encircling the petiole base
- interpetiolar : between the petioles of two opposite leaves.
- intrapetiolar : between the petiole and the subtending stem

Venation (arrangement of the veins)

rhubarb There are two subtypes of venation, craspedodromus (the major veins stretch up to the margin of the leaf) and camptodromous (major veins come close to the margin, but bend before they get to it).
- Feather-veined, reticulate — the veins arise pinnately from a single mid-vein and subdivide into veinlets. These, in turn, form a complicated network. This type of venation is typical for dicotyledons.
- Pinnate-netted, penniribbed, penninerved, penniveined; the leaf has usually one main vein (called the mid-vein), with veinlets, smaller veins branching off laterally, usually somewhat parallel to each other; eg Malus (apples).
- Three main veins originate from the base of the lamina, as in Ceanothus.
- Palmate-netted, palmate-veined, fan-veined; several main veins diverge from near the leaf base where the petiole attaches, and radiate toward the edge of the leaf; e.g. most Acer (maples).
- Parallel-veined, parallel-ribbed, parallel-nerved, penniparallel — veins run parallel most the length of the leaf, from the base to the apex. Commissural veins (small veins) connect the major parallel veins. Typical for most monocotyledons, such as grasses.
- Dichotomous — There are no dominant bundles, with the veins forking regularly by pairs; found in Ginkgo and some pteridophytes.
pteridophyte

Leaf terminology

;Shape See Leaf shape

Margins (edge)

The leaf margin is characteristic for a genus and aids in determining the species.
- entire: even; with a smooth margin; without toothing
- ciliate: fringed with hairs
- crenate: wavy-toothed; dentate with rounded teeth, such as Fagus (beech)
- dentate: toothed, such as Castanea (chestnut)
- coarse-toothed: with large teeth
- glandular toothed: with teeth that bear glands.
- denticulate: finely toothed
- doubly toothed: each tooth bearing smaller teeth, such as Ulmus (elm)
- lobate: indented, with the indentations not reaching to the center, such as many Quercus (oaks)
- palmately lobed: indented with the indentations reaching to the center, such as Humulus (hop).
- serrate: saw-toothed with asymmetrical teeth pointing forward, such as Urtica (nettle)
- serrulate: finely serrate
- sinuate: with deep, wave-like indentations; coarsely crenate, such as many Rumex (docks)
- spiny: with stiff, sharp points, such as some Ilex (hollies) and Cirsium (thistles).

Tip of the leaf

- acuminate: long-pointed, prolonged into a narrow, tapering point in a concave manner.
- acute: ending in a sharp, but not prolonged point
- cuspidate: with a sharp, elongated, rigid tip; tipped with a cusp.
- emarginate: indented, with a shallow notch at the tip.
- mucronate: abruptly tipped with a small short point, as a continuation of the midrib; tipped with a mucro.
- mucronulate: mucronate, but with a smaller spine.
- obcordate: inversely heart-shaped, deeply notched at the top.
- obtuse: rounded or blunt
- truncate: ending abruptly with a flat end, that looks cut off.

Base of the leaf

- acuminate: coming to a sharp, narrow, prolonged point.
- acute: coming to a sharp, but not prolonged point.
- auriculate: ear-shaped
- cordate: heart-shaped with the norch away from the stem.
- cuneate: wedge-shaped.
- hastate: shaped like an halberd and with the basal lobes pointing outward.
- oblique: slanting.
- reniform: kidney-shaped but rounder and broader than long.
- rounded: curving shape.
- sagittate: shaped like an arrowhead and with the acute basal lobes pointing downward.
- truncate: ending abruptly with a flat end, that looks cut off.

Surface of the leaf

The surface of a leaf can be described by several botanical terms:
- farinose: bearing farina; mealy, covered with a waxy, whitish powder.
- glabrous: smooth, not hairy.
- glaucous: with a whitish bloom; covered with a very fine, bluish-white powder.
- glutinous: sticky, viscid.
- papillate, papillose: bearing papillae (minute, nipple-shaped protuberances).
- pubescent: covered with erect hairs (especially soft and short ones)
- punctate: marked with dots; dotted with depressions or with translucent glands or colored dots.
- rugose: deeply wrinkled; with veins clearly visible.
- scurfy: covered with tiny, broad scalelike particles.
- tuberculate: covered with tubercles; covered with warty prominences.
- verrucose: warted, with warty outgrowths.
- viscid, viscous: covered with thick, sticky secretions.

Hairiness (trichomes)

Leaves can show several degrees of hairiness. The meaning of several of the following terms can overlap. See also : Trichome.
- glabrous: no hairs of any kind present.
- arachnoid, arachnose: with many fine, entangled hairs giving a cobwebby appearance.
- barbellate: with finely barbed hairs (barbellae).
- bearded: with long, stiff hairs.
- bristly: with stiff hair-like prickles.
- canescent: hoary with dense grayish-white pubescence.
- ciliate: marginally fringed with short hairs (cilia).
- ciliolate: minutely ciliate.
- floccose: with flocks of soft, woolly hairs, which tend to rub off.
- glandular: with a gland at the tip of the hair.
- hirsute: with rather rough or stiff hairs.
- hispid: with rigid, bristly hairs.
- hispidulous: minutely hispid.
- hoary: with a fine, close grayish-white pubescence.
- lanate, lanose: with woolly hairs.
- pilose: with soft, clearly separated hairs.
- puberulent, puberulous: with fine, minute hairs.
- pubescent: with soft, short and erect hairs.
- scabrous, scabrid: rough to the touch
- sericeous: silky appearance through fine, straight and appressed (lying close and flat) hairs.
- silky: with adpressed, soft and straight pubescence.
- stellate, stelliform: with star-shaped hairs.
- strigose: with appressed, sharp, straight and stiff hairs.
- tomentose: densely pubescent with matted, soft white woolly hairs.
- cano-tomentose: between canescent and tomentose
- felted-tomentose: woolly and matted with curly hairs.
- villous: with long and soft hairs, usually curved.
- woolly: with long, soft and tortuous or matted hairs.

Adaptations

In order to survive in a harsh environment, leaves can adapt in the following ways:
- Hairs develop on the leaf surface to trap humidity in dry climates, creating a large boundary layer to lessen water loss
- Leaves rustle to move humidity away from the surface reducing the boundary layer resistance between the leaf and the air.
- Plant prickles are modified clusters of epidermal hairs
- Waxy leaf surfaces form to prevent water loss
- Small, shiny leaves to deflect the sun's rays
- Thicker leaves to store water (e.g. rhubarb)
- Change to spines instead of laminar (blade) leaves (e.g. cactus)
- Shrink (to phyllodes) or disappear (with the appearance of cladodes), as photosynthetic functions are transferred to the leaf stem (Acacia species)
- Change shape to deflect wind or reduce wind resistance
- Leaves to trap insects (e.g. pitcher plant)
- Change to bulb parts to store food (e.g. onion)
- Produce aromatic oils to deter herbivores (e.g. eucalypts)
- Protect as spines, which are modified leaves.

External links

- [http://www.ibiblio.org/botnet/glossary/b_i.html Position and Arrangement] Category:Photosynthesis Category:Plant physiology Category:plant morphology Category:Plant anatomy ko:잎 ja:葉 th:ใบไม้

Flower

:This article is about the plants; for other uses see Flower (disambiguation). Flower (disambiguation) Flower (Latin flos, floris; French fleur), a term popularly used for the bloom or blossom of a plant, is the reproductive structure of those plants classified as angiosperms (flowering plants; Division Magnoliophyta). The flower structure incorporates the reproductive organs, and its function is to produce seeds through sexual reproduction. For the higher plants, seeds are the next generation, and serve as the primary means by which individuals of a species are dispersed across the landscape. After fertilization, portions of the flower develop into a fruit containing the seed(s).

Flower anatomy

Flowering plants are heterosporangiate (producing two types of reproductive spores) and the pollen (male spores) and ovules (female spores) are produced in different organs, but these are together in a bisporangiate strobilus that is the typical flower. A flower is regarded as a modified stem (Eames, 1961) with shortened internodes and bearing, at its nodes, structures that may be highly modified leaves. In essence, a flower structure forms on a modified shoot or axis with an apical meristem that does not grow continuously (growth is determinate). The stem is called a pedicel, the end of which is the torus or receptacle. The parts of a flower are arranged in whorls on the torus. The four main parts or whorls (starting from the base of the flower or lowest node and working upwards) are as follows: flower
- calyx – the outer whorl of sepals; typically these are green, but are petal-like in some species.
- corolla – the whorl of petals, which are usually thin, soft and colored to attract insects that help the process of pollination.
- androecium (from Greek andros oikia: man's house) – one or two whorls of stamens, each a filament topped by an anther where pollen is produced. Pollen contains the male gametes.
- gynoecium (from Greek gynaikos oikia: woman's house) – one or more pistils. The female reproductive organ is the carpel: this contains an ovary with ovules (female gametes). A pistil may consist of a number of carpels merged together, in which case there is only one pistil to each flower, or of a single individual carpel (the flower is then called apocarpous). The sticky tip of the pistil, the stigma, is the receptor of pollen. The supportive stalk, the style becomes the pathway for pollen tubes to grow from pollen grains adhering to the stigma, to the ovules, carrying the reproductive material. carpel Although the floral structure described above is considered the "typical" structural plan, plant species show a wide variety of modifications from this plan. These modifications have significance in the evolution of flowering plants and are used extensively by botanists to establish relationships among plant species. For example, the two subclasses of flowering plants may be distinguished by the number of floral organs in each whorl: dicotyledons typically having 4 or 5 organs (or a multiple of 4 or 5) in each whorl and monocotyledons having three or some multiple of three. The number of carpels in a compound pistil may be only two, or otherwise not related to the above generalization for monocots and dicots. In the majority of species, individual flowers have both pistils and stamens as described above. These flowers are described by botanists as being perfect, bisexual, or hermaphrodite. However, in some species of plants the flowers are imperfect or unisexual: having only either male (stamens) or female (pistil) parts. In the latter case, if an individual plant is either male or female the species is regarded as dioecious. However, where unisexual male and female flowers appear on the same plant, the species is considered monoecious. Some flowers with both stamens and a pistil are capable of self-fertilization, which does increase the chance of producing seeds but limits genetic variation. The extreme case of self-fertilization occurs in flowers that always self-fertilize, such as the common dandelion. Conversely, many species of plants have ways of preventing self-fertilization. Unisexual male and female flowers on the same plant may not appear at the same time, or pollen from the same plant may be incapable of fertilizing its ovules. The latter flower types, which have chemical barriers to their own pollen, are referred to as self-sterile or self-incompatible. (See also: Plant sexuality) Plant sexuality Additional discussions on floral modifications from the basic plan are presented in the articles on each of the basic parts of the flower. In those species that have more than one flower on an axis, the collection of flowers is termed an inflorescence. In this sense, care must be exercised in considering what is a flower. In botanical terminology, a single daisy or sunflower for example, is not a flower but a flower head—an inflorescence comprised of numerous small flowers (sometimes called florets). Each small flower may be anatomically as described above.

Floral formula

A floral formula is a way to represent the structure of a flower using specific letters, numbers, and symbols. Typically, a general formula will be used to represent the flower structure of a plant family rather than a particular species. The following representations are used: Ca = calyx (sepal whorl; e.g. Ca⁵ = 5 sepals)
Co = corolla (petal whorl; e.g., Co^3(x) = petals some multiple of three )
Z = add if zygomorphic (e.g., CoZ⁶ = zygomorphic with 6 petals)
A = androecium (whorl of stamens; e.g., A^∞ = many stamens)
G = gynoecium (carpel or carpels; e.g., G¹ = monocarpous)
x - to represent a "variable number"
∞ - to represent "many"
A floral formula would appear something like this: Ca⁵Co⁵A^{10 - ∞}G¹ Several other symbols are used that will have to await drawings to illustrate here (see [http://botit.botany.wisc.edu/courses/systematics/key.html]).

Flower function

family] The function of a flower is to mediate the union of male and female gametes. The process is termed pollination. Many flowers are dependent upon the wind to move pollen between flowers of the same species. Others rely on animals (especially insects) to accomplish this feat. The period of time during which this process can take place (the flower is fully expanded and functional) is called anthesis. Many flowers in nature have evolved to attract animals to pollinate the flower, the movements of the pollinating agent contributing to the opportunity for genetic recombinations within a dispersed plant population. Flowers that are insect pollinated are called entomophilous (literally "insect loving"). Flowers commonly have nectaries on their various parts that attract these animals. Bees and birds are common pollinators: both have color vision, thus selecting for "colorful" flowers. Some flowers have patterns, called nectar guides, that are evident in the ultraviolet range, visible to bees but not to humans. Flowers also attract pollinators by scent. In any case, pollinators are attracted to the plant, perhaps in search of nectar, which they eat. The arrangement of the stamens ensures that pollen grains are transferred to the bodies of the pollinator. In gathering nectar from many flowers of the same species, the pollinators transfer pollen between all of the flowers it visits. Flower scent is not always pleasant to our sense of smell. Some plants, such as Rafflesia, the titan arum, and the North American pawpaw (Asimina triloba) are pollinated by flies, so produce a scent imitating rotting meat. Other flowers are pollinated by the wind, and the flowers of these species (for example, grasses) have no need to attract pollinators and therefore tend not to be "showy". Wind pollinated flowers are referred to as anemophilous. Whereas the pollen of entomophilous flowers tends to be large grained, sticky, and contain significant protein (another "reward" for pollinators), Anemophilous flower pollen is usually small grained, very light, and of little nutritional value to insects, though it may still be gathered, in times of dearth. Honeybees and bumblebees actively gather anemophilous corn (maize) pollen, though it is of little value to them. There is much confusion about the role of flowers in allergies. For example the showy and entomophilous goldenrod (Solidago) is frequently blamed for respiratory allergies, of which it is innocent, since its pollen cannot be airborne. Instead the allergen is usually the pollen of the contemporary bloom of anemophilous ragweed (Ambrosia) which can drift for many kilometers.

Flowers in gardening and horticulture

Main and related articles at: Gardening, Horticulture, List of flowers, and Flower album Flower album

Flowers in the arts

The great variety of delicate and beautiful flowers has inspired the works of many poets, especially from the Romantic era. Famous examples include William Blake's Ah! Sun-Flower and William Wordsworth's I Wandered Lonely as a Cloud. Ah, Sun-flower weary of time,
Who countest the steps of the Sun,
Seeking after that sweet golden clime
Where the traveller's journey is done:

Where the Youth pined away with desire,
And the pale Virgin shrouded in snow
Arise from their graves, and aspire
Where my Sun-flower wishes to go. :– William Blake, Ah! Sun-Flower The Roman goddess of flowers, gardens, and the season of Spring is Flora. The Greek goddess of spring, flowers and nature is Chloris.

Flowers in everyday life

In modern times, people have sought ways to cultivate, buy, wear, or just be around flowers and blooming plants, partly because of their agreeable smell. Around the world, florists sell flowers for a wide range of events and functions that, cumulatively, encompass one's lifetime:
- For new births or Christenings
- As a corsage or boutonniere to be worn at social functions or for holidays
- For wedding flowers for the bridal party, and decorations for the hall
- As brightening decorations within the home
- As a gift of remembrance for bon voyage parties, welcome home parties, and "thinking of you" gifts
- For funeral flowers and flowers for the grieving Florists depend on an entire network of commercial growers and shippers to support this trade. To get flowers that are out of season in their country, florists contact wholesalers who have direct connections with growers in other countries to provide those flowers.

Flowers as symbols

Many flowers have important symbolic meanings in Western culture. The practice of assigning meanings to flowers is known as floriography. Some of the more common examples include:
- Red roses are given as a symbol of love, beauty, and passion.
- Poppies are a symbol of consolation in time of death. In the UK, Australia and Canada, red poppies are worn to commemorate soldiers who have died in times of war.
- Irises are a symbol of death.
- Daisies are a symbol of innocence. Flowers within art are also representative of the female genitalia, as seen in the works of artists such as Georgia O'Keefe, Imogene Cunningham, and Judy Chicago.

References

- Eames, A. J. 1961. Morphology of the Angiosperms. McGraw-Hill Book Co., New York.

External links

- [http://la.essortment.com/floweranatomy_raxw.htm Flower Anatomy]
- [http://www.flowercouncil.org Flower Council of Holland].
- [http://www.lovetoknow.com/Flowers/flowers.htm Flower Encyclopedia]
- [http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/F/Flowering.html Flowering] in [http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/ Kimball's Biology Pages]
- [http://www.mystiqueflowers.org Flowers] Flower Types & Meanings
- [http://landscaping.about.com/od/galleryoflandscapephotos/a/flower_pictures.htm Flower Pictures]
- [http://www.flower-arrangement.org Flower Arrangement]
- [http://house-flowers.com House Flowers Council].
- [http://eir.library.utoronto.ca/rpo/display/poem160.html William Blake: Ah Sun-Flower]
- [http://develop.consumerium.org/wiki/index.php/Flowers Flowers] at the Development Wiki of Consumerium Project
- [http://www.lib.ksu.edu/wildflower/drawing/simpleflower.jpg flower schematic]
- [http://www.flowerism.com Flowerism]An artist's devotion to painting of flowers
- [http://800florals.com/care/glossary.asp Glossary of Flowers] - Pictures and Names ---- A flower in a cryptic crossword could be pronounced flo-er and refer to a stream or river.
- Category:Plant anatomy Category: plant morphology Category:Reproductive system zh-min-nan:Hoe ko:꽃 ja:花 simple:Flower th:ดอกไม้

Bract

In botany, a bract is a modified or specialized leaf, from the axil of which a flower or flower stalk arises; or a bract may be any leaf associated with an inflorescence. Usually bracts are green and resemble the other leaves. However, some bracts are brightly colored and serve the function of attracting pollinators, either in concert with or instead of the tepals. A small bract is called bracteole or bractlet. Technically it is any bract that arises on a pedicel instead of subtending it. In grasses and sedges, the bracts that enclose the florets are termed glumes. Bracts that appear in a whorl are collectively called an involucre. An involucre is a common feature under the inflorescences of many umbelliferous and asteraceous plants. Each flower in an inflorescence may have its own whorl of bracts, in this case called an involucel. Many asteraceous plants have bracts both at the flower base and inflorescence base. Those at the flower base — chaff (recepticular bracts) — are usually minute. Those at the base of the inflorescence or head — the involucral bracts — are usually green, narrow, and leafy. A phyllary is another term for one of the scale-like bracts beneath the flowerhead in Asteraceae species. A prophyll is a leaf-like structure, such as a bracteole, subtending a single flower or pedicel. The term can also mean the lower bract on a peduncle. A spathe is a large bract that forms a sheath to enclose the flower cluster of certain plants such as palms. Image:Leafy-bract-Beggar-ticks.we.jpg|Bracts on Leafy-bract Beggar-tick (Bidens comosa) Image:Banana bract.jpg|Bracts surrounding a banana flower stalk Category:Plant anatomy Category: plant morphology

Cultivar

In botany, a cultivar is a cultivated selection that can be propagated reliably in a prescribed manner. This may be by seed, by grafting or it may be vegetatively propagated, i.e, be a clone. The word cultivar is a portmanteau coined from "cultivated" and "variety". Cultivars may be either particularly desirable selections from populations of a single species, or hybrids between species. Sometimes a cultivar can be placed within a species, but this is not required; in popular genera (such as Dahlia, Hosta or Rosa) the breeding lines are so complex that it would be impossible to ascribe most cultivars to any particular species.

Cultivar names

Cultivars are identified by uniquely distinguishing names. Names of cultivars are regulated by the International Code of Nomenclature for Cultivated Plants (ICNCP, commonly known as the "Cultivated Plant Code") and registered with an International Cultivar Registration Authority and conform to the rules of the ISHS (International Society for Horticultural Science) Commission for Nomenclature and Cultivar Registration. There are separate authorities for different plant-groups. In addition, cultivars may get a trademark name, protected by law (see #Trade Designations and "Selling Names"). A cultivar name consists of a botanical name (of a genus, species, infraspecific taxon, interspecific hybrid or intergeneric hybrid) followed by a cultivar epithet. The cultivar epithet is capitalised and put between single quotes: preferably it should not be italicized. Cultivar epithets published before 1 January 1959 were often given a Latin form and can be readily confused with the specific epithets in botanical names: after that date, new cultivar epithets must be in a modern vernacular language to distinguish them from botanical epithets. :Cryptomeria japonica 'Elegans' :Chamaecyparis lawsoniana 'Aureomarginata' (pre-1959 name, Latin in form) :Chamaecyparis lawsoniana 'Golden Wonder' (post-1959 name, English language) :Pinus densiflora 'Akebono' (post-1959 name, Japanese language) :Some incorrect examples: ::Cryptomeria japonica "Elegans" (double quotes are unacceptable) ::Berberis thunbergii cv. 'Crimson Pygmy' (this once-common usage is now unacceptable, as it is no longer correct to use "cv." in this context; Berberis thunbergii 'Crimson Pygmy' is correct) ::Rosa cv. 'Peace' (this is now incorrect for two reasons: firstly, the use of "cv."; secondly, "Peace" is a trade designation or "selling name" for the cultivar R. 'Madame A. Meilland' and should therefore be printed in a different typeface from the rest of the name, without any quote marks, for example: Rosa Peace.) Where several very similar cultivars exist, these are termed Cultivar Groups; the name is in normal type and capitalised as in a single cultivar, but not in single quotes, and followed by "Group" (or its equivalent in other languages) :Brassica oleracea Capitata Group (the group of cultivars including all typical cabbages) :Brassica oleracea Botrytis Group (the group of cultivars including all typical cauliflowers) :Hydrangea macrophylla Groupe Hortensis (in French) = Hydrangea macrophylla Hortensia Group (in English) Where cited with a cultivar name the Cultivar Group should be enclosed in parentheses, as follows: :Hydrangea macrophylla (Hortensia Group) 'Ayesha' Some cultivars and Cultivar Groups are so well 'fixed' or established that they 'come true from seed', meaning that the plants from a seed sowing (rather than vegetatively propagated) will show very little variation. In the past, such plants were often called by the terms 'variety', 'selection' or 'strain'; these terms (particularly variety, which has a very different botanical meaning) are best avoided with cultivated plants. Normally, however, plants grown from seed taken from a cultivar can be very variable and such seeds or seedling plants should never be labelled with, or sold under, the parent cultivar's name (See [http://www.rhs.org.uk/learning/publications/plantsman/0605/opinion.asp] an article by Tony Lord of The RHS Plant Finder).

Trade Designations and "Selling Names"

Cultivars that are still being developed and not yet ready for release to retail sale are often coded with letters and/or numbers before being assigned a name. It is common for this code name to be quoted alongside the new cultivar name or trade designation when the plant is made available commercially (for example Rosa Fascination = 'Poulmax') and this may continue, in books or magazines and on plant labels, for several years after the plant was released. Because a name that is attractive in one language may have less appeal in another country, a plant may be given different selling names from country to country. Quoting the code allows the correct identification of cultivars around the world and helps to avoid the once-common situation where the same plant might, confusingly, be sold under several different names in one country, having been imported under different aliases. Another form of what the Cultivated Plant Code calls a trade designation is the plant "variety", as defined in the UPOV Convention. Not to be confused with the botanical rank of variety.

Cultivars in the natural world

Many cultivars are "naturalized" in gardening, in other words they are planted out and largely left to their own devices. With pollination and regrowth from seed, true natural processes, the distinct cultivars will disappear over time. The cultivar's genetic material however may become part of the gene pool of a population, where it will be largely but not completely swamped. Cultivars that have originated as hybrids of different species are exotic, as is a plant from a different continent, or even a different part of the same country. They are a threat to the true type of a species, and should never be planted out in the wild, or where they are likely to cross-pollinate with their wild relatives.

Legal points

With plants produced by genetic engineering becoming more and more widely used, it is important to note that the companies producing these plants (or plants produced by traditional means) often claim a patent on their product. Thus the notion that "letting seed germinate and grow into a crop is the most natural thing in the world" is no longer appropriate; it can be illegal to harvest seeds (even in one's own fields) from a patented "variety" (which may or may not also be a cultivar) except for personal use. Such plants are often labelled "PBR", which stands for "plant breeders' rights", or "PVR", which stands for "plant variety rights"). The practice of patenting living plants is often considered unethical, especially where a "variety" has simply been selected from a wild population or is a chance sport among cultivated plants. However, where the "variety" is the result of a deliberate breeding programme by a nurseryman or plant breeder it may be the result of years of dedicated work involving painstaking trialling and selection. The patent (which is itself expensive to obtain) is thought to protect the breeder's right to obtain some financial reward for their work, normally for a limited period and geographical area.

External links

- [http://www.ishs.org/sci/icracpco.htm Latest Edition (February 2004) of The International Code of Nomenclature for Cultivated Plants]
- [http://www.ishs.org/sci/icralist/icralist.htm International Cultivar Registration Authorities]
- [http://www.hcs.ohio-state.edu/hcs/TMI/HORT234/Nomenclature.html The Language of Horticulture]
- [http://www.rhs.org.uk/learning/publications/plantsman/0605/opinion.asp Opinion piece by Tony Lord] (from The Plantsman magazine) Category: botanical nomenclature Category: Horticulture Category: Agriculture Category: Forestry ja:品種

Pink

:This article is about the color. For other uses, see Pink (disambiguation). Pink is a color made by mixing red and white and sometimes described as being a light red, but it is more accurately a bright undersaturated red. There are many different shades of this color. "Pink" was not a color word known to Shakespeare: it was invented in the 17th century to describe the light red flowers of pinks, flowering plants in the genus Dianthus, possibly named from the "pinked" edges of their petals appearing to have been cut with pinking shears.

Usage, symbolism, colloquial expressions

- While the west typically refers to adult films as "blue movies", in Japan these films are often called "Pink Movies". Associated with females and generally carries a connotation of feminine, innocent, childlike, or with other pastels as spring or flowers. Cherry blossoms tend to show pink so this relation may be hinted at as well in anime. Pink also carries a connotation of sexuality in Japan. This may be because of pink's association with women, or from the pink hue of flesh or a blush or any number of such reasons.
- Pink is the color of the snooker ball which has a 6-point value.
- The leader in the Giro d'Italia cycle race wears a pink jersey (maglia rosa); this reflects the distinctive pink-colored newsprint of the sponsoring Italian La Gazzetta dello Sport newspaper.
- Similarly, the (London) Financial Times newspaper has, since 1893, used a distinctive salmon-pink color for its newsprint, mainly as a way to distinguish itself from competitors.
- In Catholicism, Pink symbolizes joy and happiness. It is used for the Third Sunday of Advent, the Sunday of Joy at the impending birth of Jesus.
- Pink along with red is traditionally used on maps for territory ruled by the British Empire or for members of the Commonwealth of Nations.
- Pink, being a 'watered-down' red, is sometimes used in a derogatory way to describe a watered-down socialist.
- Pink is also the subject of a song by Aerosmith. Among other lines, one is "Pink is like red but not quite."

Pink in gender and sexuality

- The color of pink is now associated with womanhood, just like blue is associated with boys and manhood, although The Ladies Home Journal said the reverse was the "generally accepted rule" in an edition of 1918, describing pink as "more decided and stronger" while blue was "more delicate and dainty". Carrie, from Sex and the City, for example, is seen wearing pink dresses very often in the television series, and Elle, from the Legally Blonde movie series, prefers pink over any other color.
- The color pink also has an association with female genitalia.
- Some feminists have decried the color pink, along with dresses and skirts, as something related to the pre-feminism "old-style female", which they detest as a symbol of the oppression and limitations of that era. Although this trend persists, the current wave of feminism advocates choice, and many women have sought to reclaim aspects of the old-style female, including pink, as something to be proud of.
- Men today recently are now buying pink clothes, which was once taboo for men, now an enjoyable fad for men.
- Pink is also associated with homosexuals and bisexuals, often in the form of a pink triangle. This symbolic usage stems from the symbols used by the Nazis to label their prisoners in the concentration camps [http://www.pink-triangle.org/ptps/symbol.html]. Where Jews were forced to wear the familiar yellow stars of David, convicted homosexual men were forced to wear a pink triangle. Nowadays, it is often worn with pride. A Dutch newsgroup about homosexuality is called nl.roze, roze being Dutch for pink. In business, 'the pink pound' or 'pink dollar' refers to the spending power of the homosexual community.

Hot Pink

Hot pink also neon pink is bold and intense or, as Elsa Schiaparelli, the first to use hot pink called it, "shocking pink". Its appearance is more akin to magenta than it is to traditional pink.

External links

- [http://answers.google.com/answers/threadview?id=238733 Google Answers--Pink, Why Feminine?]

Red

Red is a color at the lowest frequencies of light discernible by the human eye. Red light has a wavelength range of roughly 630-760 nm. Lower frequencies are called infrared, or far red. Red is an additive primary color, complementary to cyan. It was once considered to be a subtractive primary color, and is still sometimes described as such in non-scientific literature; however, the colors cyan,