What weed is a fatal feast?
By Chelsie Vandaveer
August 5, 2003
killerPlants Tendrils: ~~1~~2~~3~~4~~5~~
Suggested Reading—>Click here.
The Westward Expansion of the United States began in 1807. After the Mexican War in 1848, additional territories (Texas, New Mexico, and California) were opened to those seeking land. The Civil War slowed the movement; it was spurred again by immigrants and those
left penniless by the war.
Settlers were considered fortunate if they had a wagon and a pair of oxen or mules; very lucky if they could take a cow or horse into the new lands. Domesticated animals were essential to their survival. Carrying feed was impractical; animals were left to forage on whatever plants were growing wild.
Earlier settlers of the Southwest, the Spanish knew that some plants caused their animals to go loco, crazy. The animal's behavior was drastically altered--staggering, walking in circles, running into stationary objects, weakness, and falling. Pregnant animals gave birth to horribly deformed young. Placid animals turned mean and uncontrollable. The Spanish word stuck, the plants were called locoweeds. ("Locoweed (Astragalus and Oxytropis spp.)", Poisonous Plant Research Laboratory, ARS, USDA)
Locoweeds are certain species in the closely-related genera Astragalus and Oxytropis. Most of the species are non-toxic, some provide nutritious forage, forty to fifty species are "locoweeds".
Among the locoweeds, some produce nitroglycosides which interrupt the sodium (Na+) pump and cause cells to lyse (disintegrate). Some accumulate selenium, a metal that in trace amounts is necessary for life, but in large amounts causes liver, heart, and skeletal damage. The most toxic are those that produce swainsonine, an indolizidine alkaloid that causes true locoism, along with heart failure, retarded growth, reproductive problems, and birth defects. ("Locoweed", Animal Science Department, Cornell University)
Despite the terrible effects, the animals habituate, eating locoweeds until they die. One animal grazing on locoweeds encourages others to join the fatal feast. Even recovered from locoweed poisoning, the animal can never be 'trusted'; permanent neurological damage leaves the animal prone to misadventure (accidents).
No one can be sure how many settlers lost their animals or their lives depending on those animals. The West is dotted with long abandoned homesteads. Even now, locoweeds cause livestock losses estimated in the hundreds of millions of dollars. ("Locoweed: Enough to Drive Ranchers Crazy", Sandra Avant, College of Agriculture and Home Economics, New Mexico State University, 1998)
Kansas Wildflowers and Grasses, a site produced by Mike Haddock, has several photographs of purple locoweed, Oxytropis lambertii. To view this beautiful, but deadly wildflower, click on the link:
http://www.lib.ksu.edu/wildflower/lambert.html
Rocky Mountain Rare Plants has a photograph of woolly locoweed, Astragalus mollissimus. To view this beauty, click on the link:
http://www.rmrp.com/Photo%20Pages/A/Astragalus%20mollissimaus%20100DPI.htm
killerPlants Tendrils: ~~1~~2~~3~~4~~5~~
Suggested Reading:
How did the mulberry push Westward Expansion? Plants that Changed History - December 11, 2001
Mulberries, caterpillars, and the conquest of Asia Plants that Changed History - December 4, 2001
Why was classic Southwestern architecture created? Plants that Changed History - March 29, 2005
How was bread made from lamb's quarters? Herbal Folklore - February 16, 2004
Could the snout weevil help ranchers? Renfield's Garden - August 6, 2003
What is the bois d'arc? What's in a Name? - March 29, 2002
|
BACK TO TOP
