|Sweetgum (Liquidambar styraciflua) tree along lake side in fall.|
Sweetgum (Liquidambar) is a genus of four species of flowering plants in the family Altingiaceae, though formerly often treated in the Hamamelidaceae. They are all large, deciduous trees, 25–40 m tall, with palmately 5- to 7-lobed leaves arranged spirally on the stems and length of 12.5 to 20 cm, having a pleasant aroma when crushed. Mature bark is grayish and vertically grooved. The flowers are small, produced in a dense globular inflorescence 1–2 cm diameter, pendulous on a 3–7 cm stem. The fruit is a woody multiple capsule 2–4 cm 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. In more northerly climates, sweetgum is 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, turning multiple colors.
- Liquidambar acalycina - Chang's Sweetgum (central & southern China)
- Liquidambar formosana - Chinese Sweetgum or Formosan Sweetgum (central & southern China, southern Korea, Taiwan, Laos, northern Vietnam).
- Liquidambar orientalis - Oriental Sweetgum or Turkish Sweetgum (southwest Turkey, Greece: Rhodes).
- Liquidambar styraciflua - American Sweetgum (eastern North America from New York to Texas and also eastern Mexico to Honduras).
The genus was much more widespread in the Tertiary, but has disappeared from Europe due to extensive glaciation in the north and the Alps, which has 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.
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 Lepidoptera caterpillars, such as the gypsy moth. The American Sweetgum is widely planted as an ornamental, not only within its natural range.
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 Southern United States as a substitute for chewing gum. The sap was also believed to be a cure for sciatica, weakness of nerves, etc.