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HANDBOOK OF NATURE STUDY 



duced from Europe. Willows grow not only from seeds, 

 but also from the roots and from cuttings. Try to grow 

 them from cuttings. It is easy to cultivate them, but hard 

 to kill them. Why are they well adapted for wind-breaks ? 

 Have you ever seen the caterpillar-like larvae of the large 

 sawfly on them ? (See Minnesota Entomologist's Report 

 for 1895.) 



14. Closely related to the willows are the poplars. 

 Their flower catkins also appeared very early, before or with 



FIG. 4. QUAKING ASP. Populus tremuloides. 

 a, staminate catkins ; &, pistillate catkins. About one-half natural size. 



the leaves. We found the sterile and fertile catkins on 

 different trees, the same as on willows, but the poplar cat- 

 Observations. Visit a stone quarry and a brick-yard. 



