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Maple

Maple

:See also Maple computer algebra system.

- Acer campestre - Field Maple
- Acer grandidentatum - Bigtooth Maple
- Acer griseum - Paperbark Maple
- Acer macrophyllum - Bigleaf Maple
- Acer micranthum - Komine Maple
- Acer negundo - Manitoba Maple
- Acer nigrum - Black Maple
- Acer palmatum - Japanese Maple
- Acer pensylvanicum - Striped Maple
- Acer platanoides - Norway Maple
- Acer pseudoplatanus - Sycamore Maple
- Acer rubrum - Red Maple
- Acer saccharinum - Silver Maple
- Acer saccharum - Sugar Maple Maples are trees or shrubs of the genus Acer. They are variously classified in a family of their own, the Aceraceae, or (together with the Hippocastanaceae) included in the Sapindaceae. This is a debate of very long standing, and Angiosperm Phylogeny Group favours a wide circumscription, as a matter of style. Angiosperm Phylogeny Group Maples are distinguished by opposite leaf arrangement. The leaves are usually palmately lobed, although palmate compound, pinnate compound, pinnate veined or unlobed shapes occur. The flowers are regular, pentamerous, and borne in racemes, corymbs, or umbels. Their distinctive fruits occur in pairs, called keys, shaped to spin as they fall and carry the seeds a considerable distance on the wind (see samara). The derivation of the name "acer" is uncertain, as it is a very old name. One of the options is that derives from the Latin acris (sharp), from the hardness of the wood, supposedly used for spears in the past. The leaves in most species are palmately veined and lobed, with 3-9 veins each leading to a lobe, one of which is in the middle. Several species, including the Paperbark Maple Acer griseum, Manchurian Maple Acer mandshuricum, Nikko Maple Acer maximowicziana, and Three-flower Maple Acer triflorum, have trifoliate leaves. The Manitoba Maple (Acer negundo) has pinnately compound leaves that may be simply trifoliate or may have 5, 7, or rarely 9 leaflets. One maple, the Hornbeam Maple Acer carpinifolium, has pinnately-veined simple leaves that resemble those of hornbeams. Maples flower in late winter or early spring, in most species with or just after the leaves appear, but in some before them. Their flowers are small and inconspicuous, though the effect of an entire avenue of maples in flower can be striking. They have five sepals, five petals about 1-6 mm long, 12 stamens about 6-10 mm long in two rings of six, and two pistils or a pistil with two styles. The ovary is superior and has two carpels, whose wings elongate the flowers, making it easy to tell which flowers are female. Within a few weeks to six months of flowering, the trees drop large numbers of seeds. Maples are important as cultivated ornamental plants, for syrup sources and timber production. Some species have bright autumnal leaf coloring. The Sugar Maple (Acer saccharum) is tapped for sap, which is then boiled to produce maple syrup or made into maple sugar or maple candy. Quebec is the world's largest producer of maple sugar products. The hard maple is the wood of choice for bowling pins and bowling alley lanes, and is yielded by Sugar Maple. Maples are an important early spring source of pollen and nectar for bees, especially honeybees, which use its resources for spring buildup. Maples are used as a food plant for the larvae of a number of Lepidoptera species (see List of Lepidoptera which feed on Maples). The flag of Canada depicts a stylized maple leaf and is a prominent national symbol. ;See also
- List of Danish Acer species

External links

- [http://hua.huh.harvard.edu/china/mss/volume11/Aceraceae-AGH_coauthoring.htm Flora of China draft synopsis of the family Aceraceae]
- [http://www.inh.co.jp/~hayasida/Ebunrui1.html Classification of maples]
- [http://info.kib.ac.cn/kibinfoEN/soft/2529.htm A new system of the genus Acer] Kunming Institute of Botany
- [http://www.botanical.com/botanical/mgmh/m/maples14.html Maples: herbal information from A Modern Herbal] Image:Maple leaves.jpg|Sycamore Maple leaves Image:Yellow-maple.jpg|Yellow Norway Maple leaves in autumn Image:redmaple.jpg|Red Maple trees in fall Image:TenryujiMomiji.jpg|Maple trees and bamboo in Japan Maple ko:단풍나무속 ja:カエデ

Maple computer algebra system

Maple is a general-purpose commercial computer algebra system. It was first developed in 1981 by the Symbolic Computation Group at the University of Waterloo in Waterloo, Ontario, Canada. Since 1988, it has been developed and sold commercially by Waterloo Maple Inc. (also known as Maplesoft), a Canadian company also based in Waterloo, Ontario. The current version is Maple 10.

Introduction

Maple is an interpreted, dynamically typed programming language. As is usual with computer algebra systems, symbolic expressions are stored in memory as directed acyclic graphs. Since Maple 6 the language has permitted lexically-scoped variables.

Example Maple code

The following code computes an exact solution to the linear ordinary differential equation :

\frac(x) - 3 y(x) = x

subject to initial conditions: dsolve( , y(x) );

Past releases

- Maple 10: May 10, 2005.
- Maple 9.5: April 15, 2004.
- Maple 9: June 30, 2003.
- Maple 8: April 16, 2002.
- Maple 7: July 1, 2001.
- Maple 6: December 6, 1999.
- Maple V R5: November 1, 1997.
- Maple V R4: Nov 19, 1996 ??.
- Maple V R3: March 15, 1994.
- Maple V R2: 1992
- Maple V: 1991
- Maple 4.3: 1990
- Maple 4.2: ??
- Maple 4.1: ??
- Maple 4.0: 1985
- Maple 3.3: 1985 (first publicly available version)
- Maple 3.2: ??
- Maple 3.1: ??
- Maple 3.0: ??
- Maple 2.2: ??
- Maple 2.1: ??
- Maple 2.0: ??
- Maple 1.1: ??
- Maple 1.0: December, 1979

Versions available

Maplesoft sells both student and professional editions of Maple, with a substantial difference in price (e.g., US$99 compared to US$1,995.00, respectively). Recent student editions (from version 6 onwards) have not placed computational limitations but rather come with less printed documentation. This is similar to the difference between Mathematica's student and professional editions. In releases prior to version 6, the student edition has had the following computational limitations:

- A maximum of 100 in floating point digits for computations and display.

- A maximum size of 8000 (in machine words or objects contained) for any algebraic object.

- A maximum of 3 dimensions for arrays.

External link

- [http://www.maplesoft.com/ Maplesoft Website] Category:Domain-specific programming languages Category:Computer algebra systems Category:Numerical programming languages

Bigtooth Maple

Bigtooth Maple (Acer grandidentatum) is a species of maple native to interior western North America, occurring in scattered populations from western Montana in the United States south to Coahuila in northern Mexico. It is closely related to Sugar Maple (A. saccharum), and is treated as a subspecies of it by some botanists. It is a small to medium-sized deciduous tree growing to 10–15 m tall and a trunk of 20–35 cm diameter. The bark is dark brown to gray, with narrow fissures and flat ridges creating plate-like scales; it is thin and easily damaged. The leaves are opposite, simple, 6–12 cm long and broad, with three to five deep, bluntly-pointed lobes, three of the lobes large and two small ones (not always present) at the leaf base; the three major lobes each have 3–5 small subsidiary lobules. The leaves turn golden yellow to red in fall (this trait is less reliable in warmer areas). The flowers appear with the leaves in mid spring; they are produced in corymbs of 5–15 together, each flower yellow-green, about 4–5 mm diameter, with no petals. The fruit is a paired samara (two winged seeds joined at the base), green to reddish-pink in color, maturing brown in early fall; each seed is globose, 7–10 mm diameter, with a single wing 2–3 cm long. seed Bigtooth Maple commonly grows in limestone soils but can adapt to a wide range of well-drained soils, from sand to clays to even white limestone areas. It prefers valleys, canyons, and the banks of mountain streams, primarily at higher elevations such as the sheltered canyons of the Edwards Plateau in Texas. Although continental climates prevail over all of its natural range, it grows well in the maritime climate of Vancouver. It is slow growing when young, and does not have many pests. It is occasionally planted as an ornamental tree, valued for its drought tolerance and ability to grow in rocky landscapes. Other vernacular names occasionally used include Lost Maple, Sabinal Maple, Western Sugar Maple, Uvalde Big Tooth Maple, Canyon Maple, Southwestern Big Tooth Maple, Plateau Big Tooth Maple, Limerock Maple, Wasatch Maple and Rocky Mountain Sugar Maple.

External links

- [http://plants.usda.gov/cgi_bin/topics.cgi?earl=plant_profile.cgi&symbol=ACGR3 USDA PLANTS profile on bigtooth maple] Maple, Bigtooth

Paperbark Maple

Paperbark Maple (Acer griseum) is a species of maple native to central China and commonly found elsewhere as a cultivated plant. It is a small to medium-sized tree, reaching 10-18 m tall, and has compound leaves bearing three leaflets, each 4-10 cm long and 2-6 cm broad, dark green above, bright glaucous blue-green beneath. The flowers are produced in small corymbs in spring, the fruit being a paired samara with two winged seeds about 1 cm long with a 3 cm wing. The tree is desirable in designed landscapes for its vibrant fall leaf color and shiny, exfoliating orange-red bark. The Paperbark Maple was introduced to cultivation in the United States by Ernest Henry Wilson of the Arnold Arboretum. Attempts have been made more recently to acquire new seed stock, because it is believed that the current gene pool of American specimens is dangerously small. Arnold Arboretum

References

- http://www.mtholyoke.edu/offices/botan/feat_plant/acer_gris/acer.html Maple, Paperbark

Komine Maple

The Komine Maple (Acer micranthum) is a small, often shrubby maple native to Japan; it has no regular English name, the name Komine Maple used here being derived from the Japanese name Komine-kaede (kaede = maple). It grows to 8-10 m tall, and has lobed, toothed leaves with five palmate lobes, similar to Redvein Maple (Acer rufinerve) and Amur Maple (Acer ginnala). It is one of many small maples that are used in temperate-zone landscaping, noted for the red bark on shoots up to a year old, and brilliant red fall color. The young leaves in spring also emerge red. Amur Maple

External links

- http://homepage2.nifty.com/chigyoraku/acerph20.html
- http://www.esveld.nl/htmldia/a/acmicr.htm
- http://www.inh.co.jp/~hayasida/E-repo5.html Maple, Komine

Black Maple

The Black Maple is a species of maple closely related to the Sugar Maple, and treated as a variety of it by some authors. Identification can be confusing due to the tendency of the two species to form hybrids. The simplest and most accurate method for distinguishing between the two trees is the 3-lobed leaves of the Black Maple versus the 5-lobed leaves of the Sugar Maple. The leaves of the Black Maple also tend to have a "droopy" appearance. Other differences that are not as pronounced include darker, more deeply grooved bark, slightly smaller seeds, and thicker leaf stems. The geographic range of the Black Maple is slightly more limited than the Sugar Maple, encompassing much of the northeastern United States and the extreme southeast of Canada in southern Ontario. Black Maple is used similarly to the Sugar Maple, for timber and for maple syrup production. Maple, Black

Striped Maple

The Striped Maple or Moosewood (Acer pensylvanicum) is a small tree of northern forests in eastern North America from southern Ontario east to New Brunswick and south to eastern Illinois and New Jersey, and also at high elevations in the Appalachian Mountains much farther south than in the rest of is range, to northern Georgia. Georgia] It is an attractive small tree growing to 5-10 m tall, with a trunk up to 20 cm diameter. The young bark is striped with green and white, and when a little older, brown. The leaves are broad and soft, 8-15 cm long and 6-12 cm broad, with three shallow forward-pointing lobes. The fruit is a samara. Moosewood prefers to grow as an understory tree in the shade of other trees, similar to the way Sassafras grows. It will not tolerate hot or dry climates. The spelling pensylvanicum is the one originally used by Linnaeus.

Cultivation and uses

Striped Maple is sometimes grown as an ornamental tree for its decorative bark, though it is difficult to transplant. Maple, Striped

Sycamore Maple

The Sycamore or Sycamore Maple (Acer pseudoplatanus) is one of the commonest maples in Europe, native to central Europe from France east to Poland, and south (in mountains) to northernmost Spain and Turkey. It is a deciduous tree that reaches 20-35 m tall at maturity, with a broad, domed crown. On young trees, the bark is smooth and grey but becomes rougher with age and breaks up in scales, exposing the pale brown to pinkish inner bark. The leaves are opposite, 10-25 cm long and broad with a 5-15 cm petiole, palmately-veined with five lobes with toothed edges, and dark green in colour; some cultivars have purple-tinged or yellowish leaves. The monoecious yellow-green flowers are produced in spring on 10-20 cm pendulous racemes, with 20-50 flowers on each stalk. The 5-10 mm diameter seeds are paired in samaras, each seed with a 20-40 mm long wing to catch the wind and rotate when they fall; this helps them to spread further from the parent tree. The seeds are mature in autumn about 6 months after pollination. The name "sycamore" originally belongs to the fig species Ficus sycomorus native to southwest Asia (this is the sycamore or sycomore referred to in the Bible), and was later mis-applied to this species (and others; see also Platanus) by reason of the superficial similarity in leaf shape. To avoid confusion, the full name Sycamore Maple is preferable.

Cultivation and uses

The Sycamore Maple is noted for its tolerance of urban pollution and salt spray, which makes it a popular tree for planting in cities, along roads treated with salt in winter, and in coastal localities. It is cultivated and widely naturalised north of its native range in northern Europe, notably in the British Isles and Scandinavia north to Tromsø, Norway; Reykjavik, Iceland, and Torshavn on the Faroe Islands. In North America, escapes from cultivation are most common in New England, New York City and the Pacific Northwest. It is planted in many temperate parts of the Southern Hemisphere, most commonly in New Zealand and on the Falkland Islands. It is also planted for timber production; the wood is white with a silky lustre, and hard-wearing, used for furniture and flooring. Occasional trees produce wood with a wavy grain, greatly increasing the value for decorative veneers.

Red Maple

Red Maple (Acer rubrum) is also known as Swamp Maple or Soft Maple. It is one of the most common and widespread deciduous trees of eastern North America, ranging from Lake of the Woods on the Ontario/Minnesota border, east to Newfoundland, south to near Miami, Florida, and southwest to east Texas. Red Maple is adaptable to a wide range of site conditions and can be found growing in both swamps and on poor dry soil and anywhere in between; however it is often out-competed by Sugar Maple (Acer saccharum) on mesic sites. Chlorosis can be troublesome on neutral or alkaline soils. Red Maple is a medium-sized tree, reaching heights of 20-25 m (exceptionally to 40 m) and a diameter of 1 m, and can live for 100-200 years, rarely longer. alkaline The leaves of the Red Maple are the easiest way to distinguish it from other maples. Like other American maples, they are deciduous and arranged oppositely on the twig. The leaves of Red Maples are typically 5-10 cm long and equally wide with 3-5 irregularly toothed lobes (in contrast, the leaves of the closely related Silver Maple Acer saccharinum are much more deeply notched and characteristically have 5 lobes). The upper side of the leaf is light green and the underside is whitish. The leaf stalks are usually red, as are the twigs. The leaves turn a brilliant red in autumn. Silver Maple The twigs of the Red Maple are red to greyish-brown and hairless. Dwarf shoots are present on many branches. In winter, the twigs bear clusters of flower buds, easily seen from a distance. The twigs of Red Maple are almost impossible to distinguish from those of Silver Maple, except that the latter have an unpleasant odour when bruised. Silver Maple] The flowers are single-sex, with male and female flowers in separate clusters, though usually on the same tree. The female (seed), flowers are red with 5 very small petals and sepals borne in clusters, usually at the twig tips. The male (pollen) flowers are nothing more than yellow stamens protruding from dwarf shoots on the branches. Both types of flowers are found on the same tree, but young trees may only produce one type. Flowering starts early in the year after 1-30 growing degree days. growing degree day The fruit is a samara, variable in color from red to brown to yellow. The samaras are 15-25 mm long and borne in pairs at an angle of 50-60 degrees. They mature in late May or early June. Red Maple frequently hybridizes with Silver Maple; the hybrid, known as Freeman's Maple Acer x freemanii, is intermediate between the parents.

Cultivation and uses

Red Maple is widely grown as an ornamental tree in parks and large gardens. Numerous cultivars have been selected, often for intensity of fall color, with 'October Glory' and 'Red Sunset' among the most popular. Toward its southern limit, 'Florida Flame' is preferred. Many cultivars of Freeman's Maple are also grown widely. The sap of the Red Maple can be used to produce maple syrup or sugar, but it is less sweet than that of the Sugar Maple. Red Maple is the State Tree of Rhode Island. Maple, Red

Silver Maple

The Silver Maple (Acer saccharinum) is a species of maple native to the eastern United States and adjacent parts of southeast Canada. It is a relatively fast-growing tree, commonly reaching a height of 20-30 m, exceptionally 35 m. It is often found along waterways and in wetlands, leading to the colloquial name "Water Maple". It is one of the most common trees in the United States. The leaves are palmate, 8-16 cm long and 6-12 cm broad, with deep angular notches between the five lobes. The 5-12 cm long, slender stalks of the leaves mean that even a light breeze can produce a striking effect as the silver undersides of the leaves are exposed. The flowers are in small panicles, produced before the leaves in early spring, with the seeds maturing in early summer. The seeds are winged, in pairs, small (5-10 mm diameter), the wing about 3-5 cm long. On mature trunks, the bark is gray and shaggy. On branches and young trunks, the bark is smooth and silvery gray. The Silver Maple has brittle wood, and is commonly damaged in storms. The roots are shallow and fibrous and easily invade septic fields and old drain pipes. It is, nonetheless, widely used as an ornamental tree because of its rapid growth and ease of propagation and transplanting. It is also commonly cultivated outside its native range, showing tolerance of a wide range of climates, growing successfully as far north as central Norway and south to Orlando, Florida. It can thrive in a Mediterranean climate, as at Jerusalem and Los Angeles, if summer water is provided. It is also grown in temperate parts of the Southern Hemisphere, as in Argentina and Uruguay. Silver Maple is closely related to Red Maple, and can hybridise with it, the hybrid being known as the Freeman Maple (Acer x freemanii). The Freeman Maple is a popular ornamental tree in parks and large gardens, combining the fast growth of Silver Maple with the less brittle wood and less invasive roots of Red Maple.

External link

[http://www.hort.uconn.edu/plants/a/acesac/acesac1.html UConn Plant Database: Silver Maple] Maple, Silver

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
-
- Category:Botany Category: plant morphology ms:Pokok ja:木 simple:Tree th:ต้นไม้

Genus

In biology, a genus (plural genera) is a grouping in the classification of living organisms having one or more related and morphologically similar species. In the common binomial nomenclature, the name of an organism is composed of two parts: its genus (always capitalized) and a species modifier. An example is Homo sapiens, the name for the human species which belongs to the genus Homo. See scientific classification for more details of this system. The type genus of a taxon is usually the first genus to be named and described. Families, and in plants all taxa up to division, are named after the type genus. The genus and these higher taxa are typified by a specimen that shows the characteristics of the genus. The specimen used to describe this species is preserved as the holotype and designated as a generitype in a zoological museum or a herbarium to be available for further study. A generic name in one kingdom is allowed to bear the same name as a genus or other taxon name in another kingdom (though this is discouraged by the International Code of Zoological Nomenclature). For instance, Anura is a genus of plants in the family Asteraceae and the order of frogs; Aotus is the genus of golden peas and night monkeys; Oenanthe is the genus of wheatears and water dropworts, and Prunella is the genus of accentors and self-heal. It is, however, not allowed for two genera within the same kingdom to have the same name. This explains why the platypus genus is Ornithorhynchus — although the name Platypus was chosen by George Shaw in 1799, that name had already been given to the ambrosia beetle by Johann Friedrich Wilhelm Herbst in 1793. Since beetles and platypuses are both member of the kingdom Animalia, the name Platypus could not be used for both. Johann Friedrich Blumenbach published the replacement name Ornithorhynchus in 1800.

Aceraceae

Acer L. - Maple
Dipteronia Oliver The Aceraceae (Maple family) comprises between 120-150 species of trees and shrubs. A common character is that the leaves are opposite. The most important genus is Acer, containing all but two of the species. The remaining two are in Dipteronia. As they are closely related to the Sapindaceae, several taxonomists (including the Angiosperm Phylogeny Group) group the Aceraceae and the Hippocastanaceae in that family. Current evidence shows that both Aceraceae and Hippocastanaceae are monophyletic, so they could be kept separate from Sapindaceae; it is a matter of taxonomic style.

External links

- [http://delta-intkey.com/angio/www/aceracea.htm Aceraceae] in L. Watson and M.J. Dallwitz (1992 onwards). [http://delta-intkey.com/angio/ The families of flowering plants:] descriptions, illustrations, identification, information retrieval. Category:Sapindales

Hippocastanaceae

Aesculus
Billia
Handeliodendron The Hippocastanaceae is a small family, with the most widespread genus Aesculus (the horsechestnuts), which today is taken to include Pavia (the buckeyes). However, the American genus Billia and the Chinese genus Handeliodendron should also be members of the family. A feature of the family is the palmate compound leaves. The family is closely related to the large, mostly tropical family Sapindaceae, and these days it is common for both Aceraceae and Hippocastanaceae to be included in the Sapindaceae s.l. Best evidence so far shows each of these two smaller families to be monophyletic (i.e. they are "good" groups) and to be basal to Sapindaceae. Inclusion (or not) is a matter of taxonomic opinion, rather than of hard fact.

External links

[http://delta-intkey.com/angio/www/hippocas.htm Hippocastanaceae] in L.Watson and M.J.Dallwitz. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. @ delta-intkey.com. Category:Sapindales ja:トチノキ

Angiosperm Phylogeny Group

The Angiosperm Phylogeny Group is an international group of systematic botanists who have come together to try to establish a consensus view of the taxonomy of flowering plants in the light of the rapid rise of molecular systematics. The angiosperms or flowering plants, scientific name Angiospermae, Anthophyta, Magnoliophyta etc, are one of the groups of organisms whose classification has been affected most radically as direct molecular analysis of relationships has become available. The influential classification scheme published by Arthur Cronquist in 1981, the Cronquist system, was challenged during the 1990s by improved schemes, finally laid down in the textbook by W. S. Judd and others. Modern urban legend has it that "direct analysis of the molecular content of the genetic material has made possible a much closer approach to the cladistic goal of making classification reflect descent". In practice, not all DNA data is created equal. Fortunately the DNA most plentifully present in plants, that of chloroplasts proved to be very informative. Actually this is not plant DNA, but prokaryote DNA. By bringing together researchers from major institutions world-wide, and publishing jointly, the Angiosperm Phylogeny Group have sought to provide a stable point of reference, publishing the APG-system (1998). This system is based on two chloroplast genes and one gene coding for ribosomes. This system deals mostly with higher ranks and, as there are still severe limits to our knowledge, a firm classification is not possible in all cases. The first APG classification was published in 1998; a revised version was published in 2003 (APG, 2003), and is known as APG II 2003 or just APG II. Its major innovations were:
- not to use formal, scientific names above the level of order
- to place a substantial number of taxa whose classification has traditionally been uncertain
- to offer alternative classifications for some groups, in which for example a number of families can either be regarded as separate or can be merged into a single larger family. APG II refers to such groups as "bracketed" taxa. Bracketed taxa are introduced to help cope with the transition from the older, morphologically based classifications to the newer, molecularly-based systems, since the process has tended to produce a number of rather small taxa, e.g. monogeneric families, which are inconvenient for users. As the APG authors note (p. 402), "We generally accept the opinion of specialists... but we also recognise that specialists nearly always favour splitting of groups...". Independent researchers, including members of the APG, continue to publish their own views on areas of angiosperm taxonomy, and in any case no classification is ever final; it presents a view at a particular point in time, based on a particular state of research. New results are always appearing. Nonetheless the APG publications are increasingly regarded as an authoritative point of reference. Wikipedia has adopted APG II Institutions represented among the principal authors of the APG II classification include:
- Royal Swedish Academy of Sciences
- Uppsala University, Sweden
- Royal Botanic Gardens, Kew, United Kingdom
- University of Maryland, College Park, USA
- University of Florida, Gainsville, USA
- Missouri Botanical Garden, USA with contributions from many other institutions world-wide.

References

- 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. (Available online: [http://www.blackwell-synergy.com/links/doi/10.1046/j.1095-8339.2003.t01-1-00158.x/abstract Abstract] | [http://www.blackwell-synergy.com/links/doi/10.1046/j.1095-8339.2003.t01-1-00158.x/full/ Full text (HTML)] | [http://www.blackwell-synergy.com/links/doi/10.1046/j.1095-8339.2003.t01-1-00158.x/pdf Full text (PDF)]) Category:Botany category: plant taxonomy

Leaf

: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

Leaf shape

In botany, the following terms are used to describe the shape of plant leaves: botany
- Acicular: slender and pointed
- Acuminate: tapering to a long point
- Alternate (alternifolia): Arranged alternately
- Bipinnate (bipinnata): Each leaflet also pinnate
- Cordate (cordata): Heart-shaped, stem attaches to cleft
- Cuneate: Triangular, stem attaches to point
- Deltoid: Triangular, stem attaches to side
- Digitate (digitata): Divided into finger-like lobes
- Elliptic (elliptica): Oval, with a short point
- Falcate: sickle-shaped
- Flabellate: Semi-circular, or fan-like
- Hastate: shaped like a spear point, with flaring pointed lobes at the base
- Lance-shaped, lanceolate (lanceolata): Long, wider in the middle botany
- Linear: Long and very narrow
- Lobed (lobata): With several points
- Obcordate: Heart-shaped, stem attaches to tapering point
- Oblanceolate (oblanceolata): Top wider than bottom
- Obovate: Teardrop-shaped, stem attaches to tapering point
- Opposite (oppositifolia): Leaves opposite one another
- Orbicular: Circular
- Ovate (ovata): Oval, egg-shaped, with a tapering point
- Palmate (palmata): Divided into many lobes
- Peltate (peltata): Rounded, stem underneath
- Perfoliate (perfoliata): Stem through the leaves
- Pinnate (pinnata): Two rows of leaflets
- odd pinnate : pinnate with a terminal leaflet
- paripinnate, even-pinnate : pinnate lacking a terminal leaflet
- Pinnatisect (pinnatifida): Cut, but not to the midrib
- Reniform: Kidney-shaped
- Rhomboid (rhomboidalis): Diamond-shaped
- Rosette: Leaves in close rings
- Round (rotundifolia): Circular
- Spatulate, spathulate (spathulata): Spoon-shaped
- Spear-shaped (hastata): Pointed, with barbs
- Subulate: Awl-shaped botany
- Sword-shaped (ensiformis): Long, thin, pointed
- Trifoliate, ternate (trifoliata): Divided into three leaflets
- Tripinnate (tripinnata): Each leaflet divided into three
- Unifoliate : with a single leaf
- Whorled: In circles round the stem Category:Botany Category:Plant anatomy Category: plant morphology

Pentamerism

In biology, pentamerism, also known as pentaradial symmetry, is a unique body symmetry exhibited primarily by starfish. It is rotational symmetry with respect to an angle of 72°, i.e. somewhat like radial symmetry, but less than that, with the body arranged around the axis of the mouth with five equal sectors. Category:Symmetry

Corymb

A panicle is a compound raceme, a loose, much-branched indeterminate inflorescence with pedicellate flowers (and fruit) attached along the secondary branches (in other words, a branched cluster of flowers in which the branches are racemes). This type of inflorescence is largely characteristic of grasses like oat and crabgrass
- , as well as other plants such as pistachio and mamoncillo. Note that botanists use the term paniculate in two ways: "having a true panicle type of inflorescence" as well as "having an inflorescence with the form but not necessarily the structure of a panicle". Note: technically, the inflorescence unit in a grass is the spikelet, but the arrangement of spikelets along the main stem axis is described using inflorescence terminology. A corymb is similar to a panicle with the same branching structure, but with the lower flowers having longer stems, thus giving a flattish top superficially resembling an umbel. Many species in the Maloideae, such as hawthorns and rowans, produce their flowers in corymbs. A thyrse is a compact panicle having an obscured main axis and cymose subaxes, making its paniculate nature hard to discern. Many Ceanothus species have thrysiform inflorescences, notably Ceanothus thyrsiflorus. Category: plant morphology

Fruit

In botany, a fruit is the ripened ovary—together with seeds—of a flowering plant. In many species, the fruit incorporates the ripened ovary and surrounding tissues. Fruits are the means by which flowering plants disseminate seeds. Evolution has led plants to adopt certain basic mechanisms, seemingly without close regard to the tissues involved. No one terminology really fits the enormous variety that is found among plant fruits. Botanical terminology for fruits is inexact and will remain so. In cuisine, when discussing fruit as food, the term usually refers to just those