162 



CAUSES OF THE BARRENNESS OF TREES 

 EXPLAINED. 



HAVING noticed the ^different members of trees in 

 the order of their development, we now proceed to 

 another branch of the subject, in order to advert to 

 some circumstances of the growth which are involved 

 in considerable obscurity. 



In the foregoing remarks on vegetable structure it 

 has been assumed, that every part of a plant has spe- 

 cific form and existence before expansion. That 

 there is no such thing as accretion by addition of new 

 organs, but simply by extension and amplification of 

 those already in existence. But as there are several 

 circumstances which appear to militate strongly 

 against this idea, it is necessary some explanation 

 should be given. 



The opposing circumstances are the following, 

 viz. 



If all trees of the same age and kind are formed 

 alike, and every one composed of every member or 

 part that ever will or possibly can be produced, how 

 does it happen, that one shall be fruitful and another 

 barren ? 



Why does a fine, healthy, free-growing tree show 



