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more especially when its branches and twigs assemble in tiers or massive 

 groups, as we sometimes see them ; the effect of light and shade is then 

 peculiarly striking. One great drawback from the value of the sycamore 

 is its liability to be attacked by the aphis, or green fly. It rarely happens 

 that it is not infected every season by a large species of that family ; and I 

 have occasionally seen whole plantations nearly stripped of their foliage by 

 this pest, which, by piercing the leaves, extracts the sap, and destroys them. 

 From this circumstance, a vulgar notion has arisen that its drooping unhealtby 

 appearance is caused by lightning. In exposed situations the sycamore is a 

 valuable tree : it is firm and immovable by winds, and therefore particularly 

 usefid from the shelter it affords. It looks well in the centre of a few oaks, 

 horse chesnuts, or occidental plane trees, or at the outside of groups of 

 English elms or Turkey oaks. 



A few of the most interesting subordinate trees, or such as ought only 

 to be specially introduced to give variety to a scene, rather than constitute the 

 principal or prominent features of a landscape, may here be mentioned. 



The Mountain Ash (Pyrus aucuparia) is a hardy, stiff, low, and formal 

 tree, and therefore unfit to be introduced, except for the variety which it offers 

 in its beautiful foliage and bright coral berries, which, in the autumn, are 

 very effective. A few may be associated externally with the acacia, or ash ; 

 or may take the centre of groups of thorn or maple. 



The Common Acacia, or Locust Tree, (Robinia pseudo-acacia), is a lofty 

 open tree, of quick growth. When divested of foliage, its general aspect is 

 not very interesting, its naked arms being long and over-grown ; but its beau- 

 tiful light pinnate foliage, and clustered, pinky, pea-hke flowers, make it 

 desirable for occasional introduction. Very exposed situations should not be 

 chosen, as its brittle limbs are very apt to be broken by violent winds. It 

 may take the centre of others to which it is nearly allied, as follows : — 

 Robinia microphilla, and Robinia umbraculifera (the umbrella-headed robinia), 

 — a very ornamental tree, with dense, umbrageous, dome-hke head, and few 

 large branches. 



The Birch (Betula). Of the white or common Birch, (B. alba), of 

 which there are two varieties, both having white-barked trunks, one is 

 pendulous, the other more upright. They are both light and elegant in form. 

 Coleridge calls the birch " Most beautiful of forest trees, the Lady of the 



