Liquidambar

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Liquidambar, commonly called sweetgum<ref name=GRIN>Template:Cite web</ref> (star gum in the UK),<ref name=RHSAZ>Template:Cite book</ref> gum,<ref name=GRIN/> redgum,<ref name=GRIN/> satin-walnut,<ref name=GRIN/> styrax or American storax,<ref name=GRIN/> is the only extant genus in the flowering plant family Altingiaceae and has 15 species.<ref name="powo"/> They were formerly often treated as a part of the Hamamelidaceae. They are native to southeast and east Asia, the eastern Mediterranean and North America. They are decorative deciduous trees that are used in the wood industry and for ornamental purposes.

Etymology

Both the scientific and common names refer to the sweet resinous sap (liquid amber) exuded by the trunk when cut.

Species

Extant species

Scientific name	Common name	Distribution
Liquidambar acalycina	Chang's sweet gum	central & southern China
Liquidambar cambodiana	Sdey	Cambodia
Liquidambar caudata		Fujian and Zhejiang, China
Template:Interlanguage link		south China to Vietnam
Liquidambar chingii		south China to Vietnam
Liquidambar excelsa	Template:Ill	Indonesia to Tibet. Some populations in India and Bangladesh
Liquidambar formosana	Chinese sweet gum	Vietnam, Laos, China, Taiwan and Korea
Template:Interlanguage link		southeast China
Template:Interlanguage link		north Guizhou, China
Template:Interlanguage link		Hainan, China
Liquidambar orientalis	Oriental sweetgum	southwest Turkey and Rhodes, Greece
Template:Interlanguage link		Vietnam
Template:Interlanguage link		Southeast Asia to China
Liquidambar styraciflua	American sweetgum	eastern North America from Connecticut, USA, to Nicaragua
Template:Interlanguage link		southeast Yunnan, China to Vietnam

Fossils

†Liquidambar changii - Miocene (Washington state, North America)

Description

Template:Stereo image They are all large, deciduous trees, Template:Cvt tall, with palmately 3- to 7-lobed leaves arranged spirally on the stems and length of Template:Convert, having a pleasant aroma when crushed. Their leaves can be many colors such as bright red, orange, yellow, and even purple.<ref name=Peterson>Template:Cite book</ref> Mature bark is grayish and vertically grooved.<ref name=Peterson /> The flowers are small, produced in a dense globular inflorescence Template:Convert diameter, pendulous on a Template:Convert stem. The fruit is a woody multiple capsule Template:Convert in diameter (popularly called a "gumball"), containing numerous seeds and covered in numerous prickly, woody armatures, possibly to attach to fur of animals. The woody biomass is classified as hardwood.

At higher latitudes, Liquidambars are among the last of trees to leaf out in the spring, and also among the last of trees to drop its leaves in the fall/autumn, turning multiple colors. Fall/autumn colors are most brilliant where nights are chilly, but some cultivars color well in warm climates.

Distribution

Species within this genus are native to Southeast and east Asia, the eastern Mediterranean, and eastern North America.<ref name="powo"/> Countries and regions in which they occur are: Indonesia (Nusa Tenggara, Java, Sumatra); Malaysia (Peninsular Malaysia); Thailand; Cambodia; Vietnam; China (including Tibet, Fujian, Guizhou, Hainan, Yunnan, Zhejiang), Taiwan, South Korea, Laos, Myanmar, Bhutan, Turkey, Greece (Rhodes), Nicaragua, Honduras, El Salvador, Guatemala, Belize, Mexico, and the eastern United States (from Texas to Connecticut). It is regarded as an artificially introduced species in India, Italy, Spain, and Belgium.<ref name="powo"/> In cultivation, they can be seen in warm temperate and subtropical climates around the world.

Fossil records

This genus is known in the fossil record from the Cretaceous to the Quaternary (age range: 99.7 to 0.781 million years ago).<ref>Template:Cite web</ref> The genus was much more widespread in the Tertiary, but has disappeared from Europe due to extensive glaciation in the north and the east–west oriented Alps and Pyrenees, which have served as a blockade against southward migration. It has also disappeared from western North America due to climate change, and also from the unglaciated (but nowadays too cold) Russian Far East. There are several fossil species of Liquidambar, showing its relict status today.

Uses

The wood is used for furniture, interior finish, paper pulp, veneers and baskets of all kinds. The heartwood once was used in furniture, sometimes as imitation mahogany or Circassian walnut. It is used widely today in flake and strand boards. Sweetgum is a foodplant for various caterpillars. The American sweetgum is widely planted as an ornamental, within its natural range and elsewhere.

The hardened sap, or gum resin, excreted from the wounds of the sweetgum, for example, the American sweetgum (Liquidambar styraciflua), can be chewed on like chewing gum and has been long used for this purpose in the Southern United States.<ref name=Peterson /> The sap was also believed to be a cure for sciatica, weakness of nerves, etc.

In Traditional Chinese medicine, lu lu tong, or "all roads open," is the hard, spiky fruit of native sweetgum species. It first appeared in Chinese medical literature in Omissions from the Materia Medica, by Chen Cangqi, in 720 AD. Bitter in taste, aromatic, and neutral in temperature, lu lu tong is claimed to promote the movement of blood and qi, water metabolism and urination, expels wind, and unblocks the channels. It is supposedly an ingredient in formulas for epigastric distention or abdominal pain, anemia, irregular or scanty menstruation, low back or knee pain and stiffness, edema with difficult urination, or nasal congestion.Template:Sfn

In the fall/autumn, the trees drop their hard, spiky seedpods by the hundreds, which can become a serious nuisance on pavements and lawns. Some US cities have expedited permits to remove sweetgum trees.<ref>Template:Cite web</ref>

In Louisiana folklore, a sharpened stick from this tree can be used to wound a cryptid known as the Parlangua (a hybrid of man and alligator).<ref>Template:Cite web</ref>