''Acer'' is a genus
commonly known as maples. The genus
is placed in the family Sapindaceae
. There are approximately 132 species
, most of which are native to Asia
, with a number also appearing in Europe
, northern Africa
, and North America
. Only one species, ''Acer laurinum
'', extends to the Southern Hemisphere
[Gibbs, D. & Chen, Y. (2009]
The Red List of Maples
Botanic Gardens Conservation International (BGCI)
The type species
of the genus is the sycamore maple, ''Acer pseudoplatanus
'', the most common maple species in Europe.
[van Gelderen, C. J. & van Gelderen, D. M. (1999). ''Maples for Gardens: A Color Encyclopedia'']
The maples usually have easily recognizable palmate
leaves (''Acer negundo
'' is an exception) and distinctive winged fruit
s. The closest relatives of the maples are the horse chestnuts
. Maple syrup
is made from the sap of some maple species.
The oldest known fossil definitive representative of genus ''Acer'' was described from a single leaf
found in Alaska
from the Lower Paleocene
have been found in rocks as old as 66.5 Ma
, but the samaras cannot reliably be attributed to the ''Acer'' genus.
Most maples are tree
s growing to a height of . Others are shrub
s less than 10 meters tall with a number of small trunks
originating at ground level. Most species are deciduous
, and many are renowned for their autumn leaf colour
, but a few in southern Asia and the Mediterranean region
. Most are shade-tolerant
when young and are often riparian, understory, or pioneer species rather than climax overstory trees. There are a few exceptions such as sugar maple
. Many of the root
systems are typically dense and fibrous, inhibiting the growth of other vegetation underneath them. A few species, notably ''Acer cappadocicum
'', frequently produce root sprout
s, which can develop into clonal colonies
Maples are distinguished by opposite leaf
arrangement. The leaves in most species are palmate
veined and lobed, with 3 to 9 (rarely to 13) veins each leading to a lobe, one of which is central or apical. A small number of species differ in having palmate compound, pinnate
compound, pinnate veined or unlobed leaves. Several species, including ''Acer griseum
'' (paperbark maple), ''Acer mandshuricum
'' (Manchurian maple), ''Acer maximowiczianum
'' (Nikko maple) and ''Acer triflorum
'' (three-flowered maple), have trifoliate leaves. One species, ''Acer negundo
'' (box-elder or Manitoba maple), has pinnately compound leaves that may be simply trifoliate or may have five, seven, or rarely nine leaflets. A few, such as ''Acer laevigatum
'' (Nepal maple) and ''Acer carpinifolium
'' (hornbeam maple), have pinnately veined simple leaves.
Maple species, such as ''Acer rubrum
'', may be monoecious
. The flower
s are regular, pentamerous
, and borne in raceme
s, or umbels
. They have four or five sepal
s, four or five petal
s about 1 – 6 mm long (absent in some species), four to ten stamen
s about 6 – 10 mm long, and two pistil
s or a pistil with two styles. The ovary
is superior and has two carpel
s, whose wings elongate the flowers, making it easy to tell which flowers are female. Maples flower in late winter
or early spring
, in most species with or just after the appearance of the leaves, but in some before the trees leaf out.
[Huxley, A., ed. (1992). ''New RHS Dictionary of Gardening''. Macmillan .]
Maple flowers are green, yellow, orange or red. Though individually small, the effect of an entire tree in flower can be striking in several species. Some maples are an early spring source of pollen
The distinctive fruit
s are called samaras
, "maple keys", "helicopters", "whirlybirds" or "polynoses". These seed
s occur in distinctive pairs each containing one seed enclosed in a "nutlet" attached to a flattened wing of fibrous, papery tissue. They are shaped to spin as they fall and to carry the seeds a considerable distance on the wind. People often call them "helicopters" due to the way that they spin as they fall. During World War II, the US Army developed a special airdrop supply carrier that could carry up to of supplies and was based on the maple seed. Seed maturation is usually in a few weeks to six months after flowering, with seed dispersal
shortly after maturity. However, one tree can release hundreds of thousands of seeds at a time. Depending on the species, the seeds can be small and green to orange and big with thicker seed pods. The green seeds are released in pairs, sometimes with the stems still connected. The yellow seeds are released individually and almost always without the stems. Most species require stratification
in order to germinate
, and some seeds can remain dormant in the soil for several years before germinating.
The genus ''Acer'' together with genus ''Dipteronia
'' are either classified in a family
of their own, the ''Aceraceae
'', or else classified as members of the family ''Sapindaceae
''. Recent classifications, including the Angiosperm Phylogeny Group
system, favour inclusion in ''Sapindaceae''. When put in family ''Sapindaceae'', genus ''Acer'' is put in subfamily
The genus is subdivided by its morphology into a multitude of sections and subsections.
Fifty-four species of maples meet the International Union for Conservation of Nature
criteria for being under threat of extinction in their native habitat.
Pests and diseases
The leaves are used as a food plant for the larva
e of a number of the order Lepidoptera
(see List of Lepidoptera that feed on maples
). In high concentrations, caterpillars, like the greenstriped mapleworm (''Dryocampa rubicunda
''), can feed on the leaves so much that they cause temporary defoliation of host maple trees. Aphid
s are also very common sap-feeders on maples. In horticultural applications a dimethoate
spray will solve this.
Infestations of the Asian long-horned beetle
(''Anoplophora glabripennis'') have resulted in the destruction of thousands of maples and other tree species in Illinois, Massachusetts, New Jersey, New York, and Ohio in the United States and Ontario, Canada.
Maples are affected by a number of fungal
diseases. Several are susceptible to Verticillium wilt caused by ''Verticillium
'' species, which can cause significant local mortality. Sooty bark disease
, caused by ''Cryptostroma
'' species, can kill trees that are under stress due to drought
. Death of maples can rarely be caused by ''Phytophthora
'' root rot
'' root decay. Maple leaves in late summer and autumn are commonly disfigured by "tar spot" caused by ''Rhytisma
'' species and mildew
caused by ''Uncinula
'' species, though these diseases do not usually have an adverse effect on the trees' long-term health.
[Phillips, D. H. & Burdekin, D. A. (1992). ''Diseases of Forest and Ornamental Trees''. Macmillan. .]
A maple leaf
is on the coat of arms of Canada
, and is on the Canadian flag
. The maple is a common symbol of strength and endurance and has been chosen as the national tree of Canada. Maple leaves are traditionally an important part of Canadian Forces
military regalia, for example, the military rank insignia for generals use maple leaf symbols.
There are 10 species naturally growing in the country, with at least one in each province. Although the idea of the tree as a national symbol originally hailed from the province of Quebec
where the sugar maple
is significant, today's arboreal emblem of Canada rather refers to a generic maple. The design on the flag
is an eleven-point stylization modeled after a sugar maple leaf (which normally bears 23 points).
It is also in the name of Canadian ice hockey club Toronto Maple Leafs
The first attested use of the word was in 1260 as "mapole", and it also appears a century later in Geoffrey Chaucer
's ''Canterbury Tales
'', spelled as "mapul".
The maple is also a symbol of Hiroshima
, ubiquitous in the local ''meibutsu
Some species of maple are extensively planted as ornamental tree
s by homeowners, businesses, and municipalities due to their fall colour, relatively fast growth, ease of transplanting, and lack of hard seeds that would pose a problem for mowing lawns. Particularly popular are Norway maple
(although it is considered invasive in North America), silver maple
, Japanese maple
, and red maple
. Other maples, especially smaller or more unusual species, are popular as specimen trees.
Numerous maple cultivar
s that have been selected for particular characteristics can be propagated
only by asexual reproduction
such as cuttings, tissue culture
, budding or grafting
. ''Acer palmatum
'' (Japanese maple) alone has over 1,000 cultivars, most selected in Japan, and many of them no longer propagated or not in cultivation in the Western world
. Some delicate cultivars are usually grown in pots and rarely reach heights of more than 50–100 cm.
Maples are a popular choice for the art of bonsai
. Japanese maple
(''Acer palmatum''), trident maple
(''A. buergerianum''), Amur maple
(''A. ginnala''), field maple
(''A. campestre'') and Montpellier maple
(''A. monspessulanum'') are popular choices and respond well to techniques that encourage leaf reduction and ramification
, but most species can be used.
Maple collections, sometimes called ''aceretums'', occupy space in many gardens and arboreta
around the world including the "five great W's" in England
: Wakehurst Place Garden
, Westonbirt Arboretum
, Windsor Great Park
, Winkworth Arboretum
and Wisley Garden
. In the United States
, the aceretum at the Harvard
-owned Arnold Arboretum
is especially notable. In the number of species and cultivars, the Esveld Aceretum
in Boskoop, Netherlands
, is the largest in the world.
Maples are important as sources of syrup and wood. Dried wood is often used for the smoking
of food. Charcoal from maples is an integral part of the Lincoln County Process
used to make Tennessee whiskey
They are also cultivated as ornamental plant
s and have benefits for tourism
The sugar maple
(''A. saccharum'') is tapped for sap
, which is then boiled to produce maple syrup
or made into maple sugar
or maple taffy
. It takes about of sugar maple sap to make of syrup. While any ''Acer'' species may be tapped for syrup, many do not have sufficient quantities of sugar to be commercially useful. The maple syrup industry is concentrated in Quebec, Canada and worth about half a billion Canadian dollars
Some of the larger maple species have valuable timber
, particularly Sugar maple in North America, and Sycamore maple in Europe. Sugar maple wood—often known as "hard maple"—is the wood of choice for bowling
pins, bowling alley lanes, pool cue shafts
, and butcher's blocks
. Maple wood is also used for the manufacture of wooden baseball bat
s, though less often than ash
due to the tendency of maple bats to shatter if they do break. The maple bat was introduced to Major League Baseball (MLB) in 1998 by Sam Bat
founder Sam Holman. Today it is the standard maple bat most in use by professional baseball. Maple is also commonly used in archery as the core material in the limbs of a recurve bow
due to its stiffness and strength.
Maple wood is often graded based on physical and aesthetic characteristics. The most common terminology includes the grading scale from common #2; which is unselected and often used for craft woods; common #1, used for commercial and residential buildings; clear; and select grade, which is sought for fine woodworking.
Some maple wood has a highly decorative wood grain
, known as flame maple
, quilt maple
, birdseye maple
and burl wood
. This condition occurs randomly in individual trees of several species, and often cannot be detected until the wood has been sawn, though it is sometimes visible in the standing tree as a rippled pattern in the bark.
These select decorative wood pieces also have subcategories that further filter the aesthetic looks. Crotch wood, bees wing, cats paw, old growth and mottled are some terms used to describe the look of these decorative woods.
Maples have a long history of use for furniture production in the United States.
The Cherokee Indians
would produce a purple dye from maple bark, which they used to dye cloth.
Maple is considered a tonewood
, or a wood that carries sound waves well, and is used in numerous musical instrument
s. Maple is harder and has a brighter sound than mahogany
, which is another major tonewood used in instrument manufacture.
The back, sides, and neck of most violins, violas, cellos, and double basses are made from maple.
Electric guitar necks are commonly made from maple, having good dimensional stability. The necks of the Fender Stratocaster and Telecaster were originally an entirely maple one piece neck, but later were also available with rosewood fingerboards. Les Paul desired an all maple guitar, but due to the weight of maple, only the tops of Gibson's Les Paul guitars are made from carved maple, often using quilted or flamed maple tops. Due to its weight, very few solid body guitars are made entirely from maple, but many guitars have maple necks, tops or veneers.
Maple is also often used to make bassoons and sometimes for other woodwind instruments like maple recorders.
Many drums are made from maple. From the 1970s to the 1990s, maple drum kits were a vast majority of all drum kits made, but in recent years, birch has become popular for drums once again. Some of the best drum-building companies use maple extensively throughout their mid-pro range.
Maple drums are favored for their bright resonant sound. Certain types of drum sticks are also made from maple.
As they are a major source of pollen in early spring before many other plants have flowered, maples are important to the survival of honeybees that play a commercially important role later in the spring and summer.
Maple is used as pulpwood. The fibers have relatively thick walls that prevent collapsing upon drying. This gives good bulk and opacity in paper. Maple also gives paper good printing properties.
Many maples have bright autumn foliage, and many countries have leaf-watching traditions. The sugar maple ''(Acer saccharum)'' is the primary contributor to fall "foliage season" in North America, particularly in Central Ontario, Quebec, and northern New England, New York, Wisconsin, and Michigan.
In Japan, the custom of viewing the changing colour of maples in the autumn is called ''momijigari''. Nikko and Kyoto are particularly favoured destinations for this activity. In Korea, the same viewing activity is called ''danpung-nori'' and the Seoraksan and Naejang-san mountains are among the best-known destinations.
Image:Acer cappadocicum spring.jpg|''Acer cappadocicum'' (Cappadocian maple)
Image:Acer carpinifolium.jpg|''Acer carpinifolium'' leaves
Image:Autumn Blaze Maple Foliage.jpg|''Acer'' × ''freemanii'' 'Autumn Blaze' (a cross between ''A. rubrum'' and ''A. saccharinum''
Image:Acer macrophyllum 0304.jpg|''Acer macrophyllum'' flowers and young leaves
Image:Acer laevigatum 3.jpg|''Acer laevigatum'' leaves and fruit
Image:Acer sempervirens leaves.jpg|''Acer sempervirens'' foliage
Image:Acer ginnala.jpg|''Acer ginnala'' foliage
Image:TenryujiMomiji.jpg|''Acer palmatum'' trees and bamboo in Japan
Image:Bi-colored Maple Tree.jpg|''Acer grandidentatum'' (bigtooth maple) in autumn colour
Image:Maple leaf Fcb981.JPG|''Acer platanoides'' leaf
Image:Red maple leaf.jpg|''Acer palmatum'' leaf in autumn
Image:Helicopter leaves.jpg|''Acer platanoides'' (Norway maple) samaras
Image:Paperbark Maple Acer griseum Leaves Closeup 2856px.jpg|''Acer griseum'' (paperbark maple)
* List of ''Acer'' species
* List of Award of Garden Merit maples
* Mazer – a drinking vessel made from maple wood
* List of foods made from maple
Category:Taxa named by Carl Linnaeus
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