344 DECIDUOUS TREES. 



broken into a great number of small masses, strongly defined 

 against each other ; that is to say, the lights being very bright and 

 warm, and the shadows quite decided, and yet softly shaded into 

 each other. The disposition of the shadows is rather lateral, but 

 not in strata, as on the beech. The head of the tree is remarkable 

 for its sunny expression ; the parts of the foliage which reflect the 

 light being in excess of the parts in shadow. But it lacks for this 

 reason the grander, because broader and bolder shadows that give 

 superior dignity and variety of expression to the oak, the chestnut, 

 and the hickory. The branches are very numerous, and radiate 

 with tolerably equal divergence at an angle of about forty-five de- 

 grees from the trunk. The bark is light-colored, and the tree has 

 a cheerful tone when leafless. 



In streets they should rarely be planted nearer than twenty-five 

 feet from each other, and thirty feet apart is better. 



The average yearly growth of the sugar maple is about fifteen 

 inches. It is most at home in a gravelly soil, and where such soils 

 are rich and well drained it grows rapidly, while in stiff" clay, or 

 ill-drained sandy ground, the growth is slow. In ten years after 

 planting it usually grows to about twenty or twenty-five feet in 

 height, and fifteen feet across its top. Height at maturity from 

 fifty to seventy feet. 



The Black or Rock Maple, Acer nigrum, is a variety of 

 the sugar maple, with darker and less deeply-lobed leaves, more 

 globular form, and lesser growth. 



The White or Silver-leaved Maple. Acer eriocarpiim. — 

 This native maple, so common on the banks of western streams, 

 has become, perhaps, too great a favorite for street planting. Its 

 growth is very rapid, being nearly double that of the sugar maple. 

 Its form is much looser and more spreading, becoming at maturity 

 an irregularly square-headed tree; the foliage is smaller, less 

 dense, of a lighter green on the upper surface, and the under sur- 

 face a downy white, which peculiarity gives the tree its name. The 

 stems of the leaves being small and slender, the foliage, as the 

 long branches sway in the wind, is ruffled so as to contrast the 



