ri.xL' v// /•;/■: 



:;:: 



Figure 407. — Staminate Strobili of 

 Pine. 



time bears seeds, but all reproduce by spores or by ferti- 

 lized eggs. Most of the evergreens are seed-bearing tn 

 which vary in size, but which are alike in having trunks 

 that taper from the base 

 to tip without dividing. 

 Such trunks are called 

 excurrent. The ever- 

 green group contains 

 the largest plants in the 

 world and those which 

 live to the greatest age. 

 Their foliage is usually 

 composed of dark green, 

 needle-like leaves which 

 remain attached to the 



tree for two or three years. Thus the trees always have 

 some foliage and so are termed "evergreen." 



267. Pine Tree. — The pine illustrates the plants of this 

 family. The pine has all the parts of a dowering plant 

 — stem (trunk), branches, roots, leaves, seed-producing 



organs, and fruit (cones). 



Stem. — The trunk does not 

 divide, — a marked character- 

 istic of evergreens. In a forest 

 where trees arc crowded together 

 and there is in consequence a 

 struggle t<> get Light, 'he trunks 



grow tall ami m08t of the 

 branches are near the top. 

 A cross section of a stem shows a scries of rings, known 

 as annual rings, by which the approximate age of the t: 

 can be told. In the spring when all the conditions arc at 

 their best and growth is rapid, the cells «»!' the tree art- 

 large and thin-walled, strength being sacrificed to size. 



Figure 408. — Young Cone 

 of Pine. 



