20 BULLETIN 816, U. S. DEPARTMENT OF AGRICULTURE. 



laiirel oaks, evergreen magnolia, camphor, rubber, silk oak, or grevillea, and casua- 

 riaa. Eucalypti are planted to some extent in Florida, but the climate is such that 

 only on the drier grounds of the interior are they likely to succeed, and even there 

 they are not to be compared with other excellent species of trees that may be culti- 

 vated successfully. 



TREES FOR SPECIAL PURPOSES. 



In the heart of a city, where the greatest difficulty is experienced 

 in getting trees to grow, the ailanthus will probably thrive when 

 nearly all other kinds fail. The sycamore and the London plane 

 are also good for such places. The Carolina poplar will frequently 

 grow under these conditions, and its use may sometimes be 

 warranted. 



For very narrow streets the Lombardy poplar is the best tree. 

 (Fig. 14.) Trees suitable for use within the reach of ocean spray or 

 on sandy lands near the coast are the red oak and the red or scarlet 

 maple south to Charleston, S. C, while the sweet gum and the live 

 oak are equally good from Norfolk southward and along the GuK of 

 Mexico. The red oak, sweet gum, red maple, and eastern live oak 

 are all grown successfully along the Pacific Ocean, while the Cali- 

 fornia live oak can be used from San Francisco southward. The trees 

 that endure the most alkali appear to be the bladder-nut tree,^ 

 London plane, peppermint gum,^ blue gum,^ the Washingtonia and 

 other hardy fan palms, Canary .Island date palm, the camphor 

 tree, and Acacia cyclops and Acacia retinodes. Only the first two 

 withstand severe freezing weather. The red oak and the red maple 

 are worth testing for these conditions. 



DESCRIPTIONS OF STREET TREES. 



ACACIA. 



The acacias,- or wattles, are a large group mostly of small trees 

 with showy yellow flowers. Although much used in California, many 

 of them are too small to make satisfactory shade trees, and because 

 of shallow rooting they are injurious to sidewalks. They also stump- 

 sprout badly. They thrive in regions 2 and 3 and in restricted 

 portions of regions 1 and 5. 



The Austrahan blackwood,^ blackwood acacia, or wattle, is a 

 strong, upright tree, growing to a height of 75 feet and forming a 

 well-shaped head. It is badly affected by citrus scale, and on this 

 account its planting is sometimes prohibited. 



The black wattle ^ is a strong-growing round-headed tree that 

 reaches a height of 40 feet and has dark-green leaves. 



The green wattle ^ is a rapid-growing tree, reaching a height of 

 60 feet and forming a round head with finely cut leaves. 



1 Koelreuteria paniculata. * Acacia melanoxylon R. Br. 



2 Eucalyptus amygdalina Labill. 6 Acacia decurrens mollis Lindl. 



3 Eucalyptus amygdalina angustifolia. « Acacia decurrens Willd. 



