MOST AVAILABLE TREES FOR PLANTING. 61 



GUM. 



Of the various gum trees only sweet gum, or bilsted 

 (Liquidambar styraciflua, L.) is suitable for street plant- 

 ing. This, however, is one of the very best, since it adapts 

 itself to many conditions, develops a symmetrical, narrow 

 crown, and is most attractive throughout the year. The 

 tree prefers moist, even wet ground, but grows fairly well 

 under less favorable conditions. Extreme care must be ex- 

 ercised in transplanting as the roots are tender and lose their 

 vitality if allowed to dry. The star-shaped leaves color 

 gorgeously in the fall, and when they are gone the pendent 

 spiky fruit heads adorn the tree ihroughout the winter. 

 Many of the branches are furnished with curious corky 

 ridges, or wings, sometimes upwards of an inch in width. 



Sour gum, or black gum (Nyssa sylvatica, Marsh.), also 

 called tupelo, and pepperidge, is a tree of quite different 

 character. It grows under most adverse conditions, but is 

 apparently not well suited for street planting. As an orna- 

 mental, however, it well deserves a place. 



HACKBERRY. 



A tree (Celtis occidenialis, L.) closely related to the elms, 

 but of more upright habit and thrifty in poor soils. It is 

 especially well suited to narro\v and moderately wide streets 

 and to the most trying conditions. Almost every mature 

 tree exhibits curiously knotted branchlets called "witches 

 broom," the result of disease. This, however, does no ma- 

 terial harm. (See page 106.) 



HORSE CHESTNUT. 



A tree (Acsculus hippocastanum , L.) native to the Medi- 

 terranean countries, and often planted in the cities of 

 Europe, yet not especially valuable there or here. Its fine 

 form, beautiful leaves, which unfold very early, and great 

 panicles of white flowers are its chief recommendations. It 

 is also hardy in moderately good soil, and grows with fair 



