50 



TETRANDRIA 



the bark smooth, and abounds in a mucilage of which 

 bird-lime is made. It blossoms in May, the berries 

 ripen in the Autumn, aud last throughout the 

 winter. 



Branches of this tree were sent by the ancient 

 Romans to their friends with their New-year's gifts, 

 as emblematical of good wishes ; and the custom is 

 said to be nearly as ancient as the building of Rome 

 itself. In England the houses and churches are de- 

 corated with it at Christmas to impart an air of cheer- 

 fulness to the festive season. 



In the economy of vegetation some trees preserve 

 their leaves constantly through the whole year, and 

 are not in the least influenced by the clemency or 

 inclemency of the seasons j such trees are called ever- 

 greens, of which the Holly is one. The Fir, Juniper, 

 Yew, Cedar, Cypress, and many others are of the 

 same description. These preserve their old leaves a 

 long time after the formation of the new, and 

 do not drop them at any determinate time. The 

 leaves of ever- greens in general are harder and 

 less succulent than those which are renewed an- 

 nually. 



With respect to deciduous trees, the falling off 

 of the leaves seems much to depend on the tempe- 

 rature of the atmosphere, which likewise serves to 



is cultivated by grafting it on the Ulmus montana, commonly 

 called the Wych Hasel, or Broad-leaved Elm. 



