Pomona College Journal of Economic Botany 457 



their progressive spirit by trying such a scheme in this state? The avocado 

 is the solution of the question. 



In considering trees that would be fitted to live in our city streets we are 

 confronted with a somewhat more serious problem, because of the necessarily 

 cramped space that does not allow either proper root or proper head develop- 

 ment of large trees. One of the saddest mistakes that can be made is to 

 plant a large growing tree in a narrow, cramped street that eventually 

 becomes filled and clogged with its branches. Therefore, we should constantly 

 bear in mind the sense of proportion so that the trees which we plant might 

 appear to the best advantage. Tables have been worked out by municipal 

 specialists who give the proper sizes of trees to balance and harmonize with 

 streets of certain widths and lined by buildings of certain heights. These 

 are obtainable by the person who cares, so that excessively bad mistakes need 

 not be made. 



For city planting, the Acacia has been used very much throughout the 

 state, many times in much inferior varieties. As a general thing it has so 

 brittle a wood that it is easily broken by the wind or the weight of its own 

 flowers. Some varieties, especially A. melanoxylon, the black wood Acacia, 

 sucker from the roots, thus becoming very troublesome in the parkways. There 

 are kinds, however, that if given proper and intelligent care make a very 

 attractive tree that is well worth one's bother. The vast number of varieties 

 of this genus permits much leeway of choice. 



The common camphor (Cinnamomum camphora) is frequently seen, 

 though often accused of growing ununiformly in height, when planted along 

 a street. I think that were this tree properly planted and cared for, it would 

 make a most satisfactory tree for this purpose, as it is of an upright habit 

 of growth, with a compact head and beautiful glossy foliage. In time, too, 

 it will grow to a considerable height. 



The carob tree or St. John's bread {Ceratonia siliqua) has recently 

 become something of a favorite for this line of planting. It is comparatively 

 slow of growth and spreading in habit, but if properly trained and encour- 

 aged will grow into as fine a tree as any of the more promising seedlings. 

 Its dark glossy foliage gives it a richness of color that is hard to equal, while 

 its branching head makes an ideal sun shade. It will stand dry weather, 

 heat and cold in a way that makes it valuable for planting in a varied range 

 of localities. 



Although Pittosporum undulatum is subject to scale, especially when 

 neglected, it is well adapted to street planting in the residence districts of 

 our cities. It has a profusion of sweet scented bloom in the spring, followed, 

 unfortunately, later in the season by dropping seeds and seed husks that 

 strew the ground beneath. A close relative to this tree is P. rhombifolinm, 

 quite similar in habit though probably higher growing and a little more 

 desirable than P. undulatum. 



