Liriodendron
Genus of two large deciduous trees with tulip-shaped flowers.
Wikipedia / Wikimedia Commons
Liriodendron, a genus in the magnolia family, includes just two living species of large, mostly deciduous trees. They are commonly called tulip trees because their showy flowers look a bit like tulips. Other names include tulip poplar and yellow poplar, though they aren't related to true poplars. One species, *Liriodendron tulipifera*, grows in eastern North America; the other, *Liriodendron chinense*, is native to China and Vietnam. Both can become enormous—the North American species has been known to reach 58.5 meters (192 feet) tall. Carl Linnaeus first described the genus in 1753, using *Liriodendron tulipifera* as the type species.
The trees are easy to identify by their unusual leaves, which usually have four lobes and a notched or straight tip. Leaf size ranges from 8 to 22 centimeters long and 6 to 25 centimeters wide. They are deciduous across most of their range, though each species has a semi-deciduous variety at its southern limits—in Florida and Yunnan, respectively. Tulip trees are typically tall, growing 18 to 60 meters high with trunks 60 to 120 centimeters in diameter. One notable specimen was the Liberty Tree in Annapolis, Maryland, which measured about 21.5 feet (6.6 meters) in circumference before it died in 1999. In dense groves, they can reach 58.5 meters (191.8 feet) as they compete for sunlight; open-grown trees are shorter. The trunk is usually columnar and branch-free for a long stretch, forming a compact, conical crown of slender branches. The roots are deep and spread widely.
*Liriodendron chinense* leaves are slightly larger than those of *L. tulipifera*, though there is considerable overlap. Leaf stems (petioles) are 4 to 18 centimeters long. Young trees have more deeply lobed and larger leaves than mature ones. In autumn, the leaves turn yellow or brown and yellow. Both species grow quickly in rich, moist, temperate soils. They hybridize easily, producing the artificial hybrid *Liriodendron × sinoamericanum*.
The flowers are 3 to 10 centimeters across and have nine tepals: three green outer sepals and six inner petals that are yellow-green with an orange base in *L. tulipifera* and the hybrid. Trees start flowering after about 15 years. The blooms resemble tulips in shape, and those of *L. tulipifera* have a faint cucumber scent. Stamens and pistils are arranged spirally around a central spike; the stamens fall off,
- field
- Botany
- known_for
- Tulip trees, large deciduous trees with tulip-like flowers
- species_count
- 2 extant species
- native_range
- Eastern North America; China and Vietnam
- maximum_height
- 58.5 m (192 ft) for North American species
- chromosome_count
- 2n = 38 (Liriodendron chinense)
Lore & Background
Liriodendron trees are easily recognized by their distinctive leaves, which have four lobes in most cases and a cross-cut notched or straight apex. Leaf size varies from 8–22 cm long and 6–25 cm wide. They are deciduous over most of their populations, though each species has a semi-deciduous variety at the southern limit of its range in Florida and Yunnan respectively. The flowers are 3–10 cm in diameter and have nine tepals — three green outer sepals and six inner petals which are yellow-green, with an orange flare at the base in L. tulipifera and the hybrid L. × sinoamericanum. Flowers of L. tulipifera have a faint cucumber odor. The fruit is a cone-like aggregate of samaras 4–9 cm long.
The North American species is commonly used horticulturally, the Chinese species is increasing in cultivation, and hybrids have been produced between these two allopatrically distributed species. Both species grow rapidly in rich, moist soils of temperate climates. They hybridize easily, producing L. × sinoamericanum cultivars. Various extinct species of Liriodendron have been described from the fossil record, including Liriodendron balticum and Liriodendron giganteum. Liriodendrons have been reported as fossils from the Late Cretaceous and early Tertiary of North America and central Asia, and are known widely as Tertiary-age fossils in Europe, showing a once-circumpolar northern distribution.
Reader's Guide
Liriodendron trees are significant for their great size and distinctive appearance, often protruding above the canopy of oaks, maples, and other trees in eastern North American forests. The North American species is the tallest native angiosperm tree known in North America, with the current tallest on record reaching 191.9 ft. Its wood, called poplar or tulipwood, is fine grained and stable, commonly used for cabinet and furniture framing, and was used by eastern Native Americans for construction of dugout canoes. The genus has a rich fossil record extending back to the Late Cretaceous, indicating a once-circumpolar northern distribution before becoming extinct in Europe due to glaciation. The two extant species, separated by the Pacific Ocean, hybridize readily, offering opportunities for horticultural development. The genus name Liriodendron is derived from lirio- meaning lily and -dendron meaning tree.
Did You Know?
- The North American species Liriodendron tulipifera may reach as much as 58.5 m (192 ft) in height.
- The stoutest well-authenticated tulip tree was the Liberty Tree in Maryland, which was 21.5 feet (6.6 meters) in circumference and died in 1999.
- The chromosome count of Liriodendron chinense is 2n = 38.
- The name canoewood refers to the tree's use for construction of dugout canoes by eastern Native Americans.
More in Flowering Trees & Shrubs 1-20
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