Probably everyone has gotten cockleburs in their socks or clothing, especially if you enjoy walking in riverbed areas or along cultivated fields and moist pastures. Cocklebur plants (Xanthium strumarium) produce hundreds of little football-shaped burs, about one inch (2.5 cm) long and covered with stiff, hooked spines. [Another species that is less common but widespread across North America is called spiny cocklebur (X. spinosum).
Spiny cocklebur is unmistakable with its stout, forked spines at the base of each leaf.] Each cocklebur fruit contains two seeds that may remain viable for many years. The prickly burs hook into your clothing and become tightly attached, like the Velcro® fasteners on shoes and day packs. Often the vicious burs form tangled clots in the fur of animals, and must be cut out of the hair. In fact, these remarkable burs have enabled the cocklebur plant to hitchhike all over the world.
General Information
The cocklebur is a classic example of a short-day plant (i.e. it only flowers when the nights are long). At least one leaf of a cocklebur plant needs 15 hours of darkness to undergo various complex biochemical reactions leading to the release of a hypothetical flower stimulant called "florigen." A protein leaf pigment called "phytochrome" controls the release of florigen from the leaves. One form of this pigment (P-660) is formed during the hours of darkness and is essential for the release of florigen. The phytochrome P-660 pigment is very sensitive to specific wavelengths of light, and a flash of light during the 15 hours of darkness can instantaneously convert it into another form called P-730 which inhibits the release of florigen, thus blocking the flowering process. Cocklebur plants can bloom in the tropics where the days are short and the nights are long, thus greatly increasing its range and potential for seed production. In North America cockleburs typically bloom during the fall months when the days are shorter and the nights longer. They will not bloom during the long days of summer or near a street light.
Cockleburs belong to the enormous sunflower family (Asteraceae), the largest plant family with approximately 24,000 species. The seeds are typically enclosed in a one-seeded fruit, called an achene, which is often airborne with a plume of silky hairs resembling a miniature parachute. In the cocklebur, the achenes are enclosed in a bur or involucre that is covered with hooked prickles. Another related hitchhiker in the sunflower family, called burdock (Arctium lappa), is equally adapted for clinging to animals and inanimate objects. Like the cocklebur, its hooked prickles are very difficult to remove from a shag carpet or sweater. Other hitchhikers, such as bur clover (Medicago hispida) and teasel (Dipsacus sativa) belong to the legume family (Fabaceae) and teasel family (Dipsacaceae). Teasel bristles are stiff enough to raise and straighten the nap on woolen cloth. The large, spiny heads of teasel were used in carding wool in early days. The heads were split and mounted on belts or rollers that moved over the cloth.
The tenacity of common burdock (Arctium minus) was described in an article by J. Raloff in Science News Volume 154, 1998. Burdocks are well-known for their ability to stick to bare fingers, but actually trapping an animal was unheard of. While migrating through Rock Creek Park in Washington, D.C., four ruby-throated hummingbirds became entangled in clusters of burdock fruits near the tops of this prolific weed that can grow to 6 feet (2 m). One of the birds was rescued, but the other three were so securely snared by the hooked prickles that they died right on the plants. The birds were unable to fly away, and their struggling caused them to touch other burs, ensnaring them even more. A thicket of burdock plants poses a potential death trap to small birds that might land on a cluster of the spiny burs.
Invention of Velcro
After a walk in the Swiss woods with his dog one day in 1941, Georges de Mestral was astounded by the ability of burrs to stick to his dog’s coat and his own clothes. When he got home, he shoved burrs under a microscope and saw that its barbed seed pods hooked easily with the looped fibers of his coat. He realized that he could produce a new type of fastening product.
It was not an easy task, though, eventually taking him 10 years to perfect the product, using cotton but settling on nylon. At first people laughed at the idea but by the time Georges de Mestral (1907 – 1990) received a patent for the product in 1955 the idea for the “zipperless zipper” was well received. He named the product Velcro, from the French words velours (velvet) and crochet (hook).
Today, Velcro is used almost everywhere: apparel, shoes, leashes, nuclear power plants, battle tanks, in the space shuttle and many more. All thanks to the burr plant.
More Details
Mestral's idea was met with resistance and even laughter, but the inventor "stuck" by his invention and together with a weaver at a textile plant in France, Mestral perfected his "hook and loop fastener." By trial and error he realized that nylon when sewn under infrared light, formed tough hooks for the bur side of the fastener. This design was finally patented in 1955. The inventor formed Velcro Industries to manufacture his invention and soon started selling over 60 million yards of the product each year. Today Velcro Industries is a multi-million dollar company.
Athough the word "velcro" was originally use by George de Mestral for his novel invention, it has become a common household word synonymous for "hook and loop" fasteners for clothing, shoes, straps, packs and numerous other products. Today Velcro® is the registered trademark for Velcro Industries' products, but there are other brands of similar fasteners on the market. Many people in the United States refer to facial tissue as "kleenex" because this was one of the original and popular brand names. But Kleenex® is the registered trademark of one brand of facial tissues, and there are other registered brand names, each manufactured by different companies. This illustrates a problem Velcro Industries and other inventors face when the names of their products become generic terms. Many words used frequently in everyday language were once trademarks, for example "escalator," "thermos," "cellophane," and "nylon." When names become generic terms, the U.S. Courts can deny exclusive rights to the trademark, so that other companies can produce the same type of product under a different registered brand name.
In order to protect a name it should be officially registered with the U.S. Patent and Trademark Office. When officially registered, the name is followed by ® (an R with a circle around it). Otherwise someone else can use your name for their product. This is precisely why the name Wayne's Word® is an official registered trademark; however, it is doubtful that it will ever become a household name like cellophane or Velcro®.
Cockleburs have literally hitchhiked across Europe and North America. In some lowland areas it is considered to be a troublesome weed by farmers and ranchers. But there may be at least two interesting uses for cockleburs. Because they readily attach to cloth material, they can be used as "darts" in a cocklebur dart game, and sixteen of the spiny burs can be glued together to form a perfect little poodle dog.
The final Curious © phrase:
“There is an old saying: If a man comes home with sand in his cuffs and cockleburs in his pants, don't ask him what he shot”
(Sam Snead)
