450 Pomona College Journal of Economic Botany 



its habits of growth, shape of head or production of troublesome litter. I feel 

 that one of the prime requisites of an ornamental and satisfactory street tree 

 be that it produce shade, for I can see no advantage in trees that do not. If 

 shade is not desired, a row of telephone poles or even lamp posts would be 

 much less expensive to maintain and equally as effective as .some of the formal 

 effects that are made by planting palms that soon come to resemble a row of 

 sticks crowned with bristles. Our most beautiful drives are those that, having 

 become shaded hy old trees, soften the glare of our sumiiier sun and offer a 

 restful retreat from its heat, being so far more attractive than our canyon- 

 streets, walled with trees of perpendicular or pyramidal growth, as to be 

 obviously preferable. Then in order that it may afford shade for a street, the 



Plate 194-. California Fan Palm {IVashingtonia sonorae). This photograph well shows 

 how the palm will convert a street into a canyon. If of much extent, sucii 

 an avenue would hecome tiresome. 



tree should be of an upright habit so that it will grow away from the sidewalk 

 and yet shade it. I am sure that pedestrians and autoists alike find nothing 

 more annoying than constant brushing and scratching of trees that have 

 been insufficiently pruned. Similarly, trees producing litter are to be avoided, 

 as a littered pavement is always unsightly, sometimes dangerous to the 

 pedestrian and above all a nuisance. It thus seems wise to choose not only a 

 tree that exists under such unnatural conditions, but also to select one that 

 will fulfill the requirements of an eflScient and desirable tree. 



After deciding on the variety to plant, we quite commonly dig a post hole 

 in the hard ground into which we insert a small plant, expecting it to grow. 

 This is the cheapest way to plant but the most expensive way to rear trees, 



