Maclura pomifera, commonly called Osage-orange, hedge-apple, Horse-apple, Bois d'arc, Bodark, or Bodock is a small deciduous tree or large shrub, typically growing to 8–15 metres (26–49 ft) tall. It is dioecious, with male and female flowers on different plants. The fruit, a multiple fruit, is roughly spherical, but bumpy, and 7–15 cm in diameter. It is filled with a sticky white latex. In fall, its color turns a bright yellow-green. It is not closely related to the orange: Maclura belongs to the mulberry family, Moraceae, while oranges belong to the family Rutaceae.
Maclura is closely related to the genus Cudrania, and hybrids between the two genera have been produced. In fact, some botanists recognize a more broadly defined Maclura that includes species previously included in Cudrania and other genera of Moraceae.
It was once thought that placing an Osage orange under the bed would repel spiders and insects. This practice has declined with the rise of synthetic insecticides. However, scientific studies have found that extracts of Osage orange do repel several insect species, in some studies just as well as the widely-used synthetic insect repellent DEET.
The trees range from 40–60 feet (12–18 m) high with short trunk and round-topped head. The juice is milky and acrid. The roots are thick, fleshy, covered with bright orange bark.
The leaves are arranged alternately on a slender growing shoot 3–4 feet (0.91–1.2 m) long, varying from dark to pale tender green. In form they are very simple, a long oval terminating in a slender point. In the axil of every growing leaf is found a growing spine which when mature is about 1 inch (2.5 cm) long, and rather formidable. The pistillate and staminate flowers are on different trees; both are inconspicuous; but the fruit is very much in evidence. This in size and general appearance resembles a large, yellow green orange; only its surface is roughened and tuberculated. It is, in fact, a compound fruit such as botanists call a syncarp, in which the carpels (that is, the ovaries) have grown together; thus, the great orange-like ball is not one fruit but many. It is heavily charged with milky juice which oozes out at the slightest wounding of the surface. Although the flowering is dioecious, the pistillate tree even when isolated will bear large oranges, perfect to the sight but lacking the seeds.
- Bark: Dark, deeply furrowed, scaly. Branchlets at first bright green, pubescent, during first winter they become light brown tinged with orange, later they become a paler orange brown. Branches with yellow pith, and armed with stout, straight, axillary spines.
- Wood: Bright orange yellow, sapwood paler yellow; heavy, hard, strong, flexible, capable of receiving a fine polish, very durable in contact with the ground. It has a specific gravity of 0.7736 and 1 cubic foot (0.028 m3) of the wood has a weight of 48.21 lb (21.87 kg).
- Winter buds: All buds lateral. Depressed-globular, partly immersed in the bark, pale chestnut brown.
- Leaves: Alternate, simple, 3–5 inches (7.6–13 cm) long, 2–3 inches (5.1–7.6 cm) wide, ovate to oblong-lanceolate, entire, acuminate, or acute or cuspidate, rounded, wedge-shaped or subcordate at base. Feather-veined, midrib prominent. They come out of the bud involute, pale bright green, pubescent and tomentose, when full grown are thick, firm, dark green, shining above, paler green below. In autumn they turn a clear bright yellow. Petioles slender, pubescent, slightly grooved. Stipules small, caducous.
- Flowers: June, when leaves are full grown; dioecious. Staminate flowers in racemes, borne on long, slender, drooping peduncles developed from the axils of crowded leaves on the spur-like branchlets of the previous year. Racemes are short or long. Flowers pale green, small. Calyx hairy, four-lobed. Stamens four, inserted opposite lobes of calyx, on the margin of thin disk; filaments flattened, exserted; anthers oblong, introrse, two-celled; cells opening longitudinally; ovary wanting. Pistillate flowers borne in a dense globose many-flowered head which appears on a short stout peduncle, axillary on shoots of the year. Calyx, hairy, four-lobed; lobes thick, concave, investing the ovary, and inclosing the fruit. Ovary superior, ovate, compressed, green, crowned by a long slender style covered with white stigmatic hairs. Ovule solitary.
- Fruit: Pale green globe, 4–5 inches (10–13 cm) in diameter, made up of numerous small drupes, crowded and grown together. These small drupes are oblong, compressed, rounded, often notched at the apex. They are filled with milky, latex-based juice. The seeds are oblong. The fruit is often seedless, and floats.
Osage-orange occurred historically in the Red River drainage of Oklahoma, Texas, and Arkansas and in the Blackland Prairies, Post Oak Savannas, and Chisos Mountains of Texas. It has been widely naturalized in the United States and Ontario.
The fruit has a pleasant and mild odor, but is inedible for the most part. Although it is not strongly poisonous, eating it may cause vomiting. However, the seeds of the fruit are edible. The fruit is sometimes torn apart by squirrels to get at the seeds, but few other native animals make use of it as a food source. This is unusual, as most large fleshy fruit serves the function of seed dispersal by means of its consumption by large animals. One recent hypothesis is that the Osage-orange fruit was eaten by a giant ground sloth that became extinct shortly after the first human settlement of North America. Other extinct Pleistocene megafauna, such as the mammoth, mastodon and gomphothere, may have fed on the fruit and aided in seed dispersal. An equine species that went extinct at the same time also has been suggested as the plant's original dispersal agent because modern horses and other livestock will sometimes eat the fruit.
It prefers a deep and fertile soil but it has great powers of adaptation and is hardy over most of the contiguous United States, where it is extensively used as a hedge plant. It needs severe pruning to keep it in bounds and the shoots of a single year will grow 3–6 feet (0.91–1.8 m) long. A neglected hedge will soon become fruit-bearing. It is remarkably free from insect enemies and fungal diseases. A thornless male cultivar of the species exists and is vegetatively reproduced for ornamental use.
The Osage-orange is commonly used as a tree row windbreak in prairie states, which gives it one of its colloquial names, "hedge apple". It was one of the primary trees used in President Franklin Delano Roosevelt's "Great Plains Shelterbelt" WPA project, which was launched in 1934 as an ambitious plan to modify weather and prevent soil erosion in the Great Plains states, and by 1942 resulted in the planting of 30,233 shelterbelts containing 220 million trees that stretched for 18,600 miles (29,900 km). The sharp-thorned trees were also planted as cattle-deterring hedges before the introduction of barbed wire and afterwards became an important source of fence posts.
The heavy, close-grained yellow-orange wood is very dense and is prized for tool handles, treenails, fence posts, and other applications requiring a strong dimensionally stable wood that withstands rot. Straight-grained osage timber (most is knotty and twisted) makes very good bows. In Arkansas, in the early 19th century, a good Osage bow was worth a horse and a blanket. Additionally, a yellow-orange dye can be extracted from the wood, which can be used as a substitute for fustic and aniline dyes. When dried, the wood has the highest BTU content of any commonly available North American wood, and burns long and hot.
The fruit was once used to repel spiders by placing one under the bed. Various studies have found elemol, an extract of Osage orange, to repel several species of mosquitos, cockroaches, crickets, and ticks. One study found elemol to be as effective a mosquito repellant as DEET. A patent was awarded in 2012 for an insect repelling device using Osage orange.
The earliest account of the tree was given by William Dunbar, a Scottish explorer, in his narrative of a journey made in 1804 from St. Catherine's Landing on the Mississippi River to the Ouachita River. It was a curiosity when Meriwether Lewis sent some slips and cuttings to President Jefferson in March 1804. The samples, donated by "Mr. Peter Choteau, who resided the greater portion of his time for many years with the Osage Nation" according to Lewis's letter, didn't take, but later the thorny Osage-orange was widely naturalized throughout the U.S. In 1810, Bradbury relates that he found two trees growing in the garden of Pierre Chouteau, one of the first settlers of St. Louis (apparently "Peter Choteau").
The trees acquired the name bois d'arc, or "bow-wood", from early French settlers who observed the wood being used for war clubs and bow-making by Native Americans. Meriwether Lewis was told that the people of the Osage Nation "esteem the wood of this tree for the making of their bows, that they travel many hundred miles in quest of it." Many modern bowyers assert the wood of the Osage-orange is superior even to English Yew for this purpose, though this opinion is by no means unanimous. The trees are also known as "bodark" or "bodarc" trees, most likely originating from a corruption of "bois d'arc." The Comanches also used this wood for their bows. It was popular with them because it is strong, flexible and durable. This tree was common along river bottoms of the Comanchería.
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