stebbinsJ LESSON IN WEEDS 173 



E. Special topics, special adaptations. 



F. Harmfulness. 



1. Killing of other plants. 



a. Shading. 



b. Sapping the ground. 



c. Crowding. 



2. Unsightly. 



3. Poisonous. 



a. Animals (loco weed, etc.) 



b. Man. 



4. Excessive loss of moisture. 



2. Classroom Study correlated with held study. 



A. Uses. 



1. Medicine. 



2. Protection. 



a. Shade. 



b. Wind break. 



c. Home for insects. 



3. Fertilizer. 



4. Food for animals. 



a. Birds. 



b. Horses, cattle, etc. 



c. Man. 



5. Prevent erosion and shifting, 

 a. Hil'sides and sand dunes. 



B. Remedies against. 



1. Artificial. 



a. Cultivation. 



b. Plows. 



c. Hoes. 



d. Mowers, scythes. 



e. Fires. 



2. Natural. 



a. Fires. 



b. Birds. 



c. Insects. 



d. Pasturing. 



3. Government control. . 

 a. Laws. 



C. Distribution. 



1. Transfer of entire plants or parts of plants. 



a. Wind. 



b. Water. 



