Liquidambar styraciflua

Liquidambar styraciflua, commonly known as the American sweetgum among other names,Template:Efn is a deciduous tree in the genus Liquidambar native to warm temperate areas of eastern North America and tropical montane regions of Mexico and Central America. Sweetgum is one of the main valuable forest trees in the southeastern United States, and is a popular ornamental tree in temperate climates. It is recognizable by the combination of its five-pointed star-shaped leaves (similar to maple leaves) and its hard, spiked fruits. It is currently classified in the plant family Altingiaceae, but was formerly considered a member of the Hamamelidaceae.<ref>Template:Cite encyclopedia</ref>

Names

This plant's genus name Liquidambar was first given by Linnaeus in 1753 from the Latin Template:Lang ('fluid') and the Arabic Template:Transliteration ('amber'), in allusion to the fragrant terebinthine juice or gum which exudes from the tree. Its specific epithet styraciflua is an old generic name meaning 'flowing with storax' (a plant resin).<ref name=Grimm /> The name "storax" has long been confusingly applied to the aromatic gum or resin of this species, that of L. orientalis of Turkey, and to the resin better known as benzoin from various tropical trees in the genus Styrax.

File:Amberboom (Liquidambar styraciflua) 14-04-2025 (d.j.b.) 02.jpg

Developing leaves and flower buds of a Sweetgum (Liquidambar styraciflua).

The sweetgum has a Nahuatl name, Ocotzocuahuitl, which translates to 'tree that gives pine resin' from ocotl ('pine'), tzotl ('resin'), cuahuitl ('tree'), which refers to the use of the tree's resin.<ref>Template:Cite book</ref>

The common name "sweetgum" refers to the species' "sweetish gum",<ref name=Werthner>Template:Cite book</ref> contrasting with the blackgum (Nyssa sylvatica), only distantly related, with which the sweetgum overlaps broadly in range. The species is also known as the "redgum", for its reddish bark.<ref name=Werthner />

History

The earliest known published record of L. styraciflua is in a work by Spanish naturalist Francisco Hernández published posthumously in 1615, in which he describes the species as a large tree producing a fragrant gum resembling liquid amber, whence the genus name Liquidambar. In John Ray's Historia Plantarum (1686) it is called Styrax liquida.<ref name="EB1911">{{#if: |

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                                    |This article
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  }}{{#ifeq:  ||}}</ref> However, the first mention of any use of the amber is described by Juan de Grijalva, the nephew of the governor of Cuba, in the year 1517.

Juan de Grijalva tells of gift exchanges with the Mayas "who presented them with, among other things, hollow reeds of about a span long filled with dried herbs and sweet-smelling liquid amber which, when lighted in the way shown by the natives, diffused an agreeable odour."<ref>Template:Cite book</ref> The species was introduced into Europe in 1681 by John Banister, the missionary collector sent out by Bishop Compton, who planted it in the palace gardens at Fulham in London, England.<ref name="EB1911"/>

Fossil record

An ancestor of Liquidambar styraciflua is known from Tertiary-aged fossils in Alaska, Greenland, and the mid-continental plateau of North America, much farther north than Liquidambar now grows. A similar plant is also found in Miocene deposits of the Tertiary of Europe.<ref name=Keeler />

Description

Size

L. styraciflua is a medium-sized to large tree, growing anywhere from Template:Convert in cultivation and up to Template:Convert in the wild,<ref name=Firefly /> with a trunk up Template:Convert in diameter on average.<ref name=Illick /> Trees may live to 400 years.<ref name="Cal Poly">Template:Cite web</ref> The tree is a symmetrical shape and crowns into an egg shape when the branches get too heavy after its first two years of cultivation.<ref name=Grimm />

Bark and branches

The bark attaches itself to these in plates edgewise instead of laterally, and a piece of the leafless branch with the aid of a little imagination readily takes on a reptilian form; indeed, the tree is sometimes called "alligatorwood".<ref name=Keeler /> The bark is a light brown tinged with red and sometimes gray with dark streaks and has a density of Template:Convert.<ref name=Illick>Template:Cite book</ref> It is deeply fissured with scaly ridges.<ref name=Keeler /> The branches carry layers of cork.<ref name=Liquidambar>Template:Citation</ref> The branchlets are pithy, many-angled, winged, and at first covered with rusty hairs, finally becoming red brown, gray or dark brown.<ref name=Keeler /> As an ornamental tree, the species has a drawback—the branches may have ridges or "wings" that cause more surface area, increasing weight of snow and ice accumulation on the tree. However, the wood is heavy and hard with an interlocking grain,<ref name=Grimm>Template:Cite book</ref> but is difficult to season.<ref name=New-Hall />

• 
  Small branches with edgewise plates of bark
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  Deeply ridged bark

Leaves

The leaves usually have five (but sometimes three or seven) sharply pointed palmate lobes.<ref name=Firefly /> They are Template:Convert wide on average and have three distinct bundle scars.<ref name=Leopold>Template:Cite book</ref>

They are long and broad, with a Template:Convert petiole. The rich dark green, smooth, shiny, star-shaped leaves generally turn brilliant yellow, orange, red, and purple colors in the autumn.<ref name=Grimm /> Its reds and yellows compare to those of the maples (Acer), and in addition it has the dark purples and smoky browns of the ash (Fraxinus).<ref name=Keeler>Template:Cite book</ref> However, in the northern part of its range, and where planted in colder areas, the leaves are often killed by frost while still green. On the other hand, in the extreme southern or tropical parts of its range, some trees are evergreen or semi-evergreen, with negligible fall color. The base is truncate or slightly heart-shaped.<ref name=Keeler /> They contain tannin and when bruised give a resinous fragrance.<ref name=New-Hall>Template:Cite book</ref>

While the starry five-pointed leaves of Liquidambar resemble those of some maples (Acer), Liquidambar is easily distinguished from Acer by its glossy, leathery leaves that grow in an alternate pattern, and not in pairs on the stems. Luna and promethea moth caterpillars feed on the leaves.<ref name=Rhoads />

• Summer foliage
  Summer foliage
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  Autumn foliage

Flowers

File:Liquidambar styraciflua bloom.JPG

Flower of sweetgum

The flowers typically appear in spring and persist into autumn, with some persisting into winter. They are typically about Template:Convert in diameter and are covered with hairs.<ref name=Illick /> The flowers are unisexual<ref name=Rhoads /> and greenish in color. Staminate flowers in terminal racemes Template:Convert long, the pistillate in a solitary head on a slender peduncle borne in the axil of an upper leaf. Staminate flowers destitute of calyx and corolla, but are surrounded by hairy bracts. Stamens indefinite; filaments short; anthers introrse. Pistillate flowers with a two-celled, two-beaked ovary, the carpels produced into a long, recurved, persistent style. The ovaries all more or less cohere and harden in fruit. There are many ovules but few mature.<ref name=Keeler />

Fruit

The distinctive compound fruit is hard, dry, and globose, Template:Convert in diameter, composed of numerous (40–60) capsules.<ref name=Illick /> Each capsule, containing one to two small seeds, has a pair of terminal spikes (for a total of 80–120 spikes). When the fruit opens and the seeds are released, each capsule is associated with a small hole (40–60 of these) in the compound fruit.

Fallen, opened fruits are often abundant beneath the trees; these have been popularly nicknamed "burr (or bir) balls",<ref name="Cal Poly" /> "gum balls",<ref>Missouri Botanical Garden: Liquidambar styraciflua</ref> "space bugs", "sticker balls",<ref>Template:Cite web</ref> "spike balls", or "monkey balls".<ref>Template:Cite book</ref><ref>Template:Cite web</ref>

The fruit is a multicapsular spherical head and hangs on the branches during the winter. The woody capsules are mostly filled with abortive seeds resembling sawdust.<ref name=Keeler /> The seeds are about Template:Convert thick, winged, and wind-dispersed. Goldfinches, purple finches, squirrels, and chipmunks eat the seeds of the tree.<ref name=Rhoads /> The seeds stratify within 30–90 days at Template:Convert or soaked in water for 15–20 days.<ref name=Leopold /> The long-stemmed fruit balls of Liquidambar resemble those of the American sycamore or buttonwood (Platanus occidentalis), but are spiny and remain intact after their seeds are dispersed; the softer fruits of Platanus disintegrate upon seed dispersal. The long-persisting fallen spiked fruits can be unpleasant to walk on; sweet gum is banned in some places for this reason.<ref name="Cal Poly" /> In abundance, they can leave a lawn lumpy. The winter buds are yellow brown, Template:Convert long, acute. The inner scales enlarge with the growing shoot, becoming Template:Convert long, green tipped with red.<ref name=Keeler />

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  Green fruit
• Leaf buds and fruit
  Leaf buds and fruit
• American sweetgum tree ball (spiny seed pod)
  American sweetgum tree ball (spiny seed pod)
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  Mature fruit and seed
• Winged seeds
  Winged seeds

Distribution

Sweetgum is one of the most common hardwoods in the southeastern and Mid-Atlantic United States, where it occurs naturally in lowlands from southwestern Connecticut south to central Florida, through central Ohio and west to Illinois, southern Missouri, and eastern Texas, but not colder highland areas of Appalachia or the Midwestern states. The species also occurs in Mexico from southern Nuevo León south to Chiapas, as well as in Guatemala, El Salvador, Belize, Nicaragua and Honduras. In Mexico and Central America, it is a characteristic plant of cloud forests, growing at middle elevations in various mountainous areas where the climate is humid and more temperate.<ref name=Grimm />

The US government distribution maps for this species are incorrect concerning the southern limit of distribution in Florida. This species occurs abundantly at Highlands Hammock State Park in Sebring, Highlands County, Florida, and even southwest of Lake Okeechobee.<ref>Template:Cite web</ref>

Uses

Wood

Lumber

File:Harvesting red gum trees, Richland County, South Carolina (1904).jpg

Harvesting redgum in Richland County, South Carolina, 1904

Sweetgum (Liquidambar styraciflua) is one of the most important commercial hardwoods in the Southeastern United States.Template:Sfn Its wood is bright reddish brown (with the sapwood nearly white) and may have black grain in the heartwood; it is heavy, straight, satiny, and close-grained, but not strong. It takes a beautiful polish, but warps badly in drying. The wood has a specific gravity of 0.5910. It is too liable to decay for outdoor use.<ref name=Keeler />
In the carpentry industry, the timber is referred to as satin walnut<ref name=Firefly>Template:Cite book</ref> and is one of the most important materials for plywood manufacturers. It is used for furniture, interior trim, railroad ties, cigar boxes, crates, flooring, barrels, woodenware, and wood pulp.<ref name=Sweetgum>Template:Citation</ref>

Bibliography

• Template:SilvicsTemplate:Sfn whitelist
• Template:EFloras

External links

• Template:PLANTS
• Interactive Distribution Map for Liquidambar styraciflua
• University of Michigan – Dearborn: Native American Ethnobotany of Liquidambar styraciflua
• Landscaping.about.com: American Sweetgum Trees Template:Webarchive
• Template:Cite iucn