ADAPTATION OF CONIFERS 105 



having an open round-topped head. It is somewhat diflBcult 

 to raise from seed as they are slow to germinate and the seed- 

 lings are likely to damp off unless closely watched on hot, 

 sultry days. 



Pinus densiflora is perfectly hardy, of compact habit, but 

 exceedingly slow in growth. Its density of foliage and drooping 

 habit make it a valuable ornamental tree for formal effect. 

 The foliage is a bright green. The var. globosa forms a perfectly 

 flat top. It is quite hardy and valuable for ornamental 

 planting, and is a promising asset to the newly introduced 

 conifers. 



The spruces are natives of the cold climates and should not 

 be planted extensively in the South. In northern Illinois and 

 southern Wisconsin the white, black, blue, and green Colorado 

 spruces are very often badly damaged by the red-spider. 

 When a good force of water is convenient, they are easily 

 eradicated; if not, the trees will gradually die. Like the pine, 

 spruces are easily propagated from seeds sown in the spring. 



The white spruce, Picea glauca, is perfectly hardy in the 

 extreme North. It grows in any kind of soil and can stand 

 low situations better than any other spruce. Its height is 

 about fifty to sixty feet. The trees are planted very extensively 

 for ornamental purposes on account of the plea^sing whitish- 

 green color. 



Black spruce, Picea mariana, grows in nearly the same 

 situations as the white spruce. Its habit is a regular pyramid, 

 its foliage bluish-green, and the bark lighter colored. The wood 

 is inferior in quality and snaps frequently in burning. It is a 

 beautiful tree while young and is valuable for parks and gardens 

 on account of its close, compact growth, color of foliage, and the 

 retaining of its branches close to the ground even when old. 



The Norway spruce, Picea Abies, is probably the best known 



