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MISC. PUBLICATION 16 2, U.S. DEPT. OF AGRICULTURE 



expand and grow until they finally open into flowers or leaves. 

 Some trees, as the elm and red maple, blossom and set fruit before 

 the leaves open. The pussy willow and alder catkins burst forth 

 before the frost is fairly out of the ground. Other trees wait until 

 their leaves are partly grown before producing their blossoms, while 

 still others, such as the chestnut and basswood, do not flower until 

 early summer. 



Most of the cone-bearing trees, such as the pines, spruces, and firs, 

 also blossom in the early spring. The staminate (male) and pistil- 

 late (female) flowers are usually found on the same tree, and their 

 color varies in the different species from yellow and orange to shades 

 of pink, rose, or purple. The pines, especially, produce large quan- 

 tities of pollen which is scattered by the wind. Geologically, the 



Figure 3. — An Abundant Seeding of Yellow Poplar. 



Nature has to make a bounteous provision for the survival of her tree families, for 

 only a small proportion of the seed scattered germinates. A still smaller proportion of 

 the seedlings live to reach maturity. 



conifers are very old, being contemporary with the plant growth 

 from which the coal deposits of today were formed. They still re- 

 tain the simplicity of floral structure which marked the vegetation 

 of those early times. 



Some trees mature their seeds rapidly and scatter them early in 

 the growing season. This gives the seedlings a long summer for 

 their first season's growth. Others, such as the nut trees, slowly pre- 

 pare their seeds for fall sowing. The members of the red oak group 

 and many of the cone-bearing trees take 2 years to mature their seed 

 crops. 



The seeds of many trees are winged and are easily scattered by the 

 wind. The maples, and the American elm, are among those that 

 belong in this class. The lighter seeds, like those of the elm, may 

 be borne long distances. The seeds of the maples, however, are com- 



