BIBLIOGRAPHY 289 



into the wool and skin of sheep and into the nostrils and eyes of 

 all classes of stock. 



Gramagrass. — Needle grama {Bouteloua arislidoides) is prob- 

 ably the only species of gramagrass which is mechanically 

 injurious to foraging animals. The entire spike breaks from the 

 common axis, the segments being provided with a sharp callus 

 point at the base. The effect of these segments on persons is 

 anything but pleasant. The sharp base of the spikes penetrates 

 the stockings and other clothing and then breaks off. The skin 

 is left full of " needle points." 



QUESTIONS 



1. (a) To what extent are milkweeds poisonous? {h) How may whorled 

 milkweed be recognized? To what extent does whorled milkweed cause live- 

 stock poisoning? Where does it occur? (c) What means of prevention are 

 recommended where whorled milkweed occurs more or less abundantly? 



2. Under what conditions may oak poisoning occur? 



3. (a) What species of "laurel" sometimes cause livestock poisoning? 

 {b) What are the symptoms of ' ' laurel " poisoning? What remedies are recom- 

 mended? 



4. Is rubberweed poisonous to both cattle and sheep? 



5. (a) Where does western sneezeweed occur? Is it poisonous to both 

 sheep and cattle? {h) Discuss (i) the character of sneezeweed poisoning, and 

 (2) the remedy recommended. 



6. Discuss aconite as a poisonous plant. 



7. Under what conditions does wild cherry cause livestock losses? 



8. (a) What are the results to animals that consume considerable quantities 

 of ergot? (6) What treatment is recommended for animals poisoned by ergot? 



9. (a) What is fly agaric, and to what extent does it cause livestock losses? 

 {b) Discuss death cup as a plant poisonous to pasture stock. 



10. Discuss the waj^s in which livestock is injured mechanically by vegeta- 

 tion, and the different effects produced. 



11. (a) What family of plants is the cause of a large part of the mechanical 

 injuries suffered by livestock? {b) What is the general character of these 

 mechanical injuries? (c) What genera of grasses are conspicuous because of 

 the mechanically injurious species which they embrace? 



BIBLIOGRAPHY 



Aldous, a. E. Eradicating Tall Larkspur on Cattle Ranges in the National 

 Forests. U. S. Dept. Agr. Farmers Bui. 826, 1917. 



Chesnut, V. K., and Wilcox, E. V. The Stock-Poisoning Plants of 

 Montana. U. S. Dept. of Agr., Div. of Bot., Bui. 26, 1901. 



