Liriodendron
Encyclopedia : L : LI : LIR : Liriodendron
Liriodendron is a genus in the magnolia family (Magnoliaceae) consisting of two species of large deciduous trees. Liriodendron tulipifera is native to eastern North America; Liriodendron chinense occurs in China and Vietnam. The standard English name is variously given as two words (tulip tree, the most common form in popular usage), hyphenated (tulip-tree), or compound (tuliptree, the most common form in botanical usage).
Tuliptree is sometimes called "yellow poplar", but this name should be avoided, as the closest relationship to poplars is that they are both dicotyledons. Tuliptree is in a different genus, family, order, and subclass to the poplar. Compare to poplars; class Magnoliopsida (dicotyledons), family Salicaceae, genus Populus.
Tuliptrees are easily recognized by their leaves, which are very unusual, having four lobes in most cases and a cross-cut notched or straight apex; size varies from 8-22 cm long and 6-25 cm broad, averaging slightly larger in L. chinense but with considerable overlap between the species; the petiole is 4-18 cm long. Leaves on young trees tend to be more deeply lobed and larger size than those on mature trees. In autumn the leaves turn yellow, or yellow and brown.
The flowers are 3-10 cm in diameter and have nine tepals, three short outer sepal-like, and six inner petal-like, yellow-green with (L. tulipifera) or without (L. chinense) an orange patch. They are superficially similar to a tulip in shape, hence the tree's name. Flowers of L. tulipifera have a faint cucumber odor. The stamens and pistils are arranged spirally around the spike; the stamens fall off, and the pistils become the samaras. The fruit is a cone-like aggregate of samaras 4-9 cm long, each of which has a roughly tetrahedral seed with one edge attached to the central conical spike and the other edge attached to the wing.
Like many "Arcto-Tertiary" genera, Liriodendron became extinct in Europe due to large-scale glaciation. It is known widely as fossils in Europe and well outside its natural range in Asia and North America, showing a once circumpolar distribution.
References and external links
- Hunt, D. (ed). 1998. Magnolias and their allies. International Dendrology Society & Magnolia Society. (ISBN 0-9517234-8-0)
- Parks, C. R., Wendel, J. F., Sewell, M. M., & Qiu, Y.-L. (1994). The significance of allozyme variation and introgression in the Liriodendron tulipifera complex (Magnoliaceae). Amer. J. Bot. 81 (7): 878-889 [abstract and first page]
- [Moriaty, William. The Tulip Tree in Central Florida]
- [Liriodendron chinense]
- [Liriodendron chinense trunk and flowers]
- [Kew: Plants: Tulip Trees, Liriodendron tulipifera & Liriodendron chinense]
- [Flora of China draft account of Magnoliaceae] (site currently down; see [google cache])
- [Liriodendron tulipifera images at bioimages.vanderbilt.edu]
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