W138 



CRAZYWEEDS AND POINTVETCHES 



Ox5 T 'tropis spp., syn. Ara'gallus spp. 



The crazyweeds and pointvetches form a large genus of legumes (pea 

 family, Leguminosae), containing more than 200 species, the majority occurring 

 in the Old World, with Asia the center of distribution. In the United States 

 species of Oxytropis are perennial herbs; some of the foreign members are 

 shrubs or undershrubs. On a conservative nomenclatural basis about 35 

 species are found in the 11 far-western range States. The genus is best repre- 

 sented in the Rocky Mountain States, particularly Montana, Wyoming, and 

 Colorado. The three Pacific States have only about two species each. 



The scientific name Oxytropis is Latinized from the Greek words oxus, sharp, 

 and tropis, keel, referring to the sharp beak at the tip of the lowest two 

 united petals (keel) of the flower; this genus is separated from the closely 

 related Astragalus genus chiefly on the basis of this character. Any attempt 

 to select a suitable English name for Oxyftropis is complicated by the fact 

 that it contains both harmless and loco-producing species and by the fact 

 that several species of Astragalus are also known to produce locoism. Oxy- 

 troplis species are often called stemless loco, because of the usual absence of 

 leafy stems. The book name, oxytrope, is occasionally applied to them. In 

 the interest of common name standardization, it seems desirable to restrict 

 loco to those species of Astragalus which produce locoism. Crazyweed, a name 

 already applied to the best-known species (O. lambortii), is also suggested as 

 an appropriate subgeneric name for the loco-producing species of Oxytropfe. 

 Pointvetch, referring to the characteristic vetchlike aspect and the pointed 

 keel of the flowers, a name suggested by Dr. Frederick V. Coville, has been 

 adopted here for those species of Oxytropis not known to be poisonous. 



In North America crazyweeds and pointvetches extend from sea level in 

 Alaska to elevations of about 11,000 feet in Colorado and 12,000 feet in 

 California. These plants flourish in sandy soils of grassy plains, and in 

 well-drained, sandy, or gravelly soils of open foothill and montane slopes and 

 ridges. Their deep, woody taproots and frequent dense woolly hairiness enable 

 at least many of these cold-resistive species to grow in rather dry sites, to 

 withstand extended drought, and the bleak environment of wind-swept moun- 

 tain peaks. It is noteworthy that 11 species are known to occur in Alaska. 



In general, the palatability of crazyweeds and pointvetches is poor for 

 cattle and horses and fair for sheep, although sometimes, especially in scarcity 

 of desirable forage, the plants are eaten freely. Although the genus contains 

 harmless species and is widely distributed and plentiful on many western 

 ranges, its relatively low palatability is not disadvantageous considering the 

 livestock losses caused by crazyweeds. From the range standpoint the crazy- 

 weeds are more important than the pointvetches. 



Extensive grazing of crazyweeds, like similar use of locos, induces a chronic 

 poisoning called locoism. Such plants are. habit-formers, their poisonous ef- 

 fects being cumulative, fatalities ensuing only after prolonged use. Addicted 

 animals should be shifted immediately to ranges where the plants are not 

 available, as otherwise the habit will eventuate in their ruination and death. 

 Furthermore, a loco eater is liable to teach other animals the habit. 



Among the earliest symptoms of locoism comes loss of weight, followed by 

 gait irregularities, general depression, and such extreme weakness that it is 

 sometimes mistaken for paralysis. Lack of muscular coordination and defects 

 of vision develop, due to the reactions of the plant poison on the central 

 nervous system. Emaciation and weakness increase as the disease progresses, 

 with death often resulting from starvation. 



Among domesticated animals probably horses are most seriously affected. 

 In the early stages of loco poisoning, identification of a locoed horse is diffi- 

 cult, as the animal may appear normal except for occasional crazy spells. 

 Locoed horses are usually hard to handle; they cannot be led or backed and 

 can be stopped or turned only with difficulty ; occasionally they leap over 

 small pebbles in the road or try to step across a sizable stream. An abnormal 

 growth of mane and tail is another characteristic of loco poisoning. 



Cattle display similar symptoms to horses, except that they shake their 

 heads more or less violently, particularly after exertion. At times cattle also 

 tremble markedly, and their eyes become staring. 



