384 



CONIFERS 



LABORATORY 



In the laboratory examine a cross section of the stem to see the dif- 

 ference in the cells grown in the early and in the late part of a season. 

 Note the pith and medullary rays. If specimens are available, examine 

 sections of wood from different trees. Make a collection of the woods 

 found in the vicinity. Examine scales from staminate and carpellate 

 cones. With the microscope examine pollen of pine. Draw and describe 

 all the rays. 



270. Economic Importance. — The value of the gym- 

 nosperms can scarcely be overestimated. Most of the 



Figure 418. — Planting Young Trees in the Adirondacks. 



trees are sawed into lumber for building purposes, but 

 some of them are used in their natural form for telegraph 

 poles, masts of ships, and timbers of mines. Wood pulp, 

 from which most of our paper is made, is produced from 

 small spruce trees. The by-products of this group of 

 trees are of great value. From the pine come tar, pitch, 

 turpentine, and resin, while the bark of the hemlock was 

 formerly extensively used in tanning leather. 



