STREET TREES. 29 



overcome. The tree is practically disease and insect free, with the 

 exception of a liability to infestation by a loaf aphis ^ which pro- 

 duces yellow spots on the leaves and causes them to drop prema- 

 turely; also, the honeydew which they produce is so abundant at 

 times as to cover the leaves and wet the sidewalk beneath the 

 tree, the leaves under certain weather conditions becoming blackened 

 with dust accumulating and a fungus growing in the secretion, 

 thereby giving the tree an unsightly appearance. This aphis, how- 

 ever, is not always present and does not seriously injure the tree. 

 The Norway maple comes into leaf later than most of the other 

 maples, but holds its leaves later in the fall. They usually assume 

 a bright yellow hue before they drop. The leaves are preceded 

 by an abundance of yellow-gi'een blossoms. On account of its dense 

 shade and masses of fine fibrous roots it is difficult to grow grass 

 under this tree. Its good shape and attractive dark-green foliage 

 make it popular for street planting in spite of its dense, low head. 

 It will succeed in regions 1, 2, 3, 4, 9, 10, 11, and 12. 



The Oregon maple ^ is the large-leaved maple of the northern 

 Pacific slope. It forms a large round head, and with its unusually 

 large dark-green leaves makes a very attractive street tree that 

 succeeds well in regions 1, 2, 3, and 4. It is valuable and worthy 

 of more extended cultivation on the Pacific coast. 



The red maple,^ scarlet maple, or swamp maple is one of the 

 most widely distributed of American trees. It is found from Canada 

 to the Gulf of Mexico and west to the Rocky Mountains. Its leaves 

 are the smallest of any of the eastern native maples, but it grows 

 large and the trees are usually of rather upright outline. It is 

 better adapted to suburban conditions than to city streets and is 

 one of the few trees that succeed well near the ocean. It has bright- 

 red blossoms before the leaves appear. The young leaves and fruits 

 are also red. The mature leaves begin to color early, some branches 

 coloring as early as the middle of July, assuming brilliant reds and 

 yellows and staying on later than those of the sugar maple. It is 

 a handsome tree that is not as much used as it deserves to be in 

 regions 1, 9, 10, 11, 12, and 13. 



The silver maple,^ also called the soft maple, white maple, and 

 swamp maple, is probably more used for street planting through 

 the whole United States than any other tree, and with one excep- 

 tion it is the least desirable. It is usually planted because it is a 

 quick-growing tree, but it is not more rapid in growth than several 

 other much better trees. There are three serious objections to its 

 use as a street tree. The first is its brittle wood, which at an early 



1 Periphyllus lyropictus Kess. (Data furnished ^ Acer rubrum L. 



by the Bureau of Entomology.) * Acer saccharinum L. 



2 Acer macrophyllum Pursh. 



