28 September 2013

Osage orange tree (Maclura pomifera)

Osage orange fruit (Maclura pomifera)

Maclura pomifera is a deciduous tree and I was fortunate enough to be able to photograph the fruit and the foliage of this fascinating tree.  The fruit is about the size of a tennis ball and looks quite unusual and in my view if it wasn't a bright neon green colour it could easily be mistaken for the brain of a small mammal. 

    What is particularly fascinating about the fruit of this tree is that scientific studies have found that extracts of Osage orange acts as a natural insect repellent as it contains a substance called elemol which is said 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.

I read on the internet that the whole fruit left in a room for a couple of weeks is said to repel cockroaches, ants and spiders.  The fruit should be thrown out when the bright green colour becomes brown.  As well, the oil extracted from the crushed fruit also works as a repellent. 

Here is a link to a published scientific abstract which describes the efficacy of elemol and amyris oil as a tick repellent.

Osage orange foliage and fruit

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 7.6–15 centimetres (3–6 in) 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.

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 fruit 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.

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 oldest Osage orange is located at River Farm, in Alexandria, VA, and is believed to have been a gift from Thomas Jefferson.

Ecological aspects
The fruit is not poisonous and humans can generally eat it without ill effects, but it is considered inedible due to the texture and taste, which has been described as chemical-like. Exposure to frost improves the flavour, which becomes cucumber-like. The seeds of the fruit are edible and it is sometimes torn apart by squirrels to get at the seeds, but few other native animals make use of it as a food source.

The Osage orange is commonly used as a tree row windbreak in prairie states, which gives it one of its colloquial names, "hedge apple". 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.

Related Posts Plugin for WordPress, Blogger...