76 PASTORAL AND AGRICULTURAL BOTANY 



It is very different in its appearance from the former two loco plants. 

 The stems are ascending, or decumbent, 2-4 in. high becoming small ovate 

 to oblong leaflets, 19-21 in number to each compound leaf. The plant has 

 in its vegetative condition a rough resemblance to alfalfa. The flowers 

 are produced in a dense spike and are blue, purple, or violet in color. 

 The pods are inflated, hence bladder-like and in the immature sta e are 

 streaked with purple. 



Loco Weeds in General. The three plants described above are usually 

 considered together as loco weeds. They have occasioned the poisoning 

 of horses, cattle and sheep in the field. The wooly loco weed poisons horses 

 generally, and is rarely injurious to cattle, which will not eat the plant 



FIG. 32. Case 8. Steer pastured on stemless loco-weed (Aragallus Lamberti.) 

 Showing the effect of the plant in leaping unnecessarily high in going over a rut in 

 the road. (After Marsh, C. Dwight: The Loco-weed Disease of the Plains, Bulletin 112, 

 Bureau of Animal Industry, Plate III, Fig. 4, June 28, 1909.) 



readily. Horses as a rule begin to feed upon the plant when they are short 

 of food. Both the wooly and stemless loco weeds are green during the 

 winter, when all the plains grasses are dry and brown. Hence, they are 

 especially dangerous in the spring, when the horses and cattle are turned 

 out to pasture. Once the animals feed upon the plant, they acquire the 

 habit and this shows the development of a depraved appetite, which was 

 attributed by some to the presence of tape worms. 



Symptoms. The symptoms of poisoning in horses are quite marked. 

 A high-spirited horse becomes dull followed by irregular gait and irregular 

 mode of feeding. The horse drags its feet more or less (Fig. 33). Asso- 

 ciated with this partial paralysis is an apparent loss of muscular control 



