DECIDUOUS TREES. 359 



color. The branches spring close to the ground, and form a low, 

 loose, wide-spreading head. The seeds are borne conspicuously 

 in autumn, and add much to the beauty of the tree. The leaves 

 die off a rich yellow. Naked young wood smooth and pea-green, 

 with long spaces between the buds. Usual height and breadth 

 about twenty feet. The tree grows rapidly, and is not long-lived. 



The Curled Ash-leaved Negundo, JV. crispum, is princi- 

 pally marked by curled leaves, and has no superior beauty. 



THE POPLAR. Populus. 



The poplars are all remarkable for a more or less tremulous 

 motion of their leaves. All are rapid growers, some species ex- 

 ceeding all other native trees in this quality. We have seen a 

 Cottonwood, Populus cajiadensis, spring from the seed and attain a 

 height of sixty feet in twenty years. 



The smaller species, such as the aspen, are short-lived trees, 

 and their greatest beauty is attained young. A moist, warm soil 

 suits them best. 



The species of poplar are very numerous, and we shall de- 

 scribe only a few which have the most distinct character, or which, 

 from their abundant distribution, should be known. All have 

 catkins or blossoms which appear in the spring before the leaves, 

 many of them with cottony attachments. They are not ornamental, 

 and are often annoying, while floating in the air, or scattered on 

 the ground. 



The following are the most prominent among the poplars : 



The American Aspen. P. tremula trepida. — This is the 

 American type of that trembling sensitiveness to every breath of 

 air which has made its English prototype the theme of a thousand 

 poetic similes. Its small heart-shaped leaves, vibrating on slender 

 petioles, seem to be ever in a buzz of excitement. No tree in the 

 forest comes earlier into leaf, although the buckeye displays greater 

 massiveness of early foliage. The exquisitely-delicate green of its 

 first leaves is one of the most charming sights of the spring, while 

 all through the summer their murmuring vibrations never cease 



