STEMS AND BRANCHES 



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of very irregular growth is the Catalpa (Indian Bean), 

 shown in Fig. 4. The tendency to grow irregularly 

 usually increases with age. The Buttonwood, for ex- 

 ample, grows quite regu- 

 larly until it reaches the 

 age of thirty to forty 

 years; then its new 

 branches grow in pecu- 

 liarly irregular ways. 

 The twigs of a very old 

 and a young Apple-tree 

 illustrate this change 

 which age produces. 



There are great differ- 

 ences in the color and 

 surface of the bark of 

 the twigs of different 

 species of trees; some 

 are green (Sassafras), 

 some red (Peach, on the sunny side), some purple (Cherry). 

 Some are smooth and dotless, some marked with dots 

 (Birch), some roughened with corky ridges (Sweet 

 Gum), etc. 



The taste and odor of the bark are characteristics 

 worthy of notice : the strong, fragrant odor of the Spice- 

 bush ; the fetid odor of the Papaw ; the aromatic taste of 

 the Sweet Birch ; the bitter taste of the Peach ; the mu- 

 cilaginous Slippery Elm; the strong-scented, resinous, 

 aromatic Walnut, etc. 



The branches of trees vary greatly in the thickness 

 of their tips and in their tendency to grow erect, hori- 

 zontal, or drooping. Thus the delicate spray of the 

 Birches contrasted with the stout twigs of the Ailanthus, 

 or the drooping twigs of the Weeping Willow with the 

 erect growth of the Lombardy Poplar, give contrasts of 

 the strongest character. In the same way, the direc- 

 tions the main branches take in their growth from the 



Fig. 4. 



