272 WESTERN GRAZING GROUNDS AND FOREST RANGES 



other western states in which post mortems proved 

 beyond all reasonable doubt that the deaths were caused 

 by eating the leaves of the choke cherry bushes through 

 which the trail-hungry sheep were driven. Sheep in this 

 condition should never be driven through such thickets, 

 if it is possible to avoid it. 



Sleepy Grass (Stipa vaseyi). This is a plant peculiar 

 to the high mountains of Arizona and New Mexico. In 

 appearance it is not unlike wild rye, growing to a height 

 of from three to four feet. Local stock will not touch 

 it, except when but a few inches high, and the only ani- 

 mals affected are those driven through the ranges and 

 unfamiliar to the country. There are no records of 

 cattle or sheep being affected by it, horses being the 

 only stock on which any observations have been made. 



I once saw a six-horse team belonging to a party trav- 

 eling through the country turned out to graze near a 

 large patch of this grass. The horses were very hungry, 

 and the grass looked good to them. When the teamster 

 tried to hitch up his animals some of them began to 

 fall asleep as they stood in the harness. Their heads 

 would drop lower and lower and sometimes the animals 

 would sink to the ground, there to sleep soundly. If 

 touched sharply they would jump all over, as if awakened 

 from a dream, but drop off to sleep again at once, if 

 left alone. This sleepiness disappears in a few hours, 

 and to all outward appearances the animals are none 

 the worse for the experience. 



Foxtail (Hordeum) and Squirrel Tail Grass. The in- 

 jurious effects of these grasses are entirely mechanical 

 in their nature. The sharp awns or spikes of the 

 plants work their way into the inner lining of the ani- 

 mal's lips and mouth, also affecting the tongue. They 



