STOCK-POISOXIXG PLANTS OF THE RANGE O 



THE GRASS FAMILY (POACEAE) 



SLEEPY GRASS (STIPA VASEYI) 



Sleepy grass (Stipa vaseyi) is found in the southwestern part of 

 the United States from western Texas to Arizona and as far north 

 as Colorado. Although it is not important from the standpoint of 

 stock losses, it perhaps should be mentioned because of the peculiar 

 interest attached to its effect. It is shown in Plate 1 and is a tall, 

 coarse grass which can be readily distinguished from the other 

 grasses. In Lincoln and Otero Counties, N. Mex., in the general 

 region of the Sacramento and Sierra Blanca Mountains, it has long 



Figure 1. — A horse fast asleep after 



ing sleepy 



been known to produce the peculiar, narcotic effect on horses which 

 has given it its name. Horses go to sleep and may remain asleep for 

 a day or more. Parties traveling with pack trains sometimes have 

 their horses so affected that they are obliged to wait in camp for their 

 recovery. Figure 1 shows a horse in a sound sleep. It is a curious 

 fact that outside the region mentioned the plant is not known to be 

 poisonous: feeding experiments with the plant in both green and 

 dry stages from this locality have produced definite and pronounced 

 effect, whereas the plant from other neighborhoods in Xew Mexico 

 was nontoxic. The experiments indicate that cattle are not affected, 

 and sheep only slightly, although there are reports of cattle losses. 

 It seems probable that there are few if any actual losses from sleepy 

 grass, so that it is of little importance to stockmen on the range. 



