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as 3 J/2 feet in diameter, but in the Rocky Mountains it is 

 seldom one-half this size, and trees taken from the far 

 northwest do not thrive well on the Atlantic coast, owing 

 to the much greater rainfall which they naturally receive 

 there; the cones of the Douglas spruce are from 2 to 4 

 inches long, pendant on the branches, their scales rounded 

 and shorter than the bracts which project beyond them. 



The hemlock spruces (Tsuga) are planted between the 

 approach to the elevated railway station and the power 

 house, and are represented by the Canadian hemlock spruce 

 (Tsuga canadensis), the same species which forms the inter- 

 esting forest on the hills bordering the Bronx River, and 

 indicated on the general plan of the Garden as the hemlock 

 grove. This tree occasionally becomes about 90 feet high, 

 with a trunk up to 12 feet in diameter, and is distributed 

 throughout northeastern North America, extending south- 

 ward along the mountains to Alabama, northward to Nova 

 Scotia and westward to Minnesota. Its bark is the most 

 important tanning substance in the United States and a 

 great many trees are annually felled to obtain it; its wood 

 furnishes a cheap lumber of little strength and durability. 

 The weeping hemlock (Tsuga canadensis pendula) is one 

 of the most beautiful dwarf evergreens. The Carolina hem- 

 lock (Tsuga caroliniana), from the mountains of southern 

 Virginia to Georgia, may also be seen here, as well as the 

 Japanese hemlock spruce (Tsuga Tsuga), to which the name 

 Tsuga was first applied. The hairy-twigged Japanese hem- 

 lock, Tsuga diver sijolia, is also here. 



In the area to the westward of the conservatories, 

 extending to the west border, and bounded by paths on 

 the north and south, are the firs (Abies). These can at 

 once be distinguished from the spruces (Picea) by the erect, 

 instead of pendulous, cones, and by the smooth branchlets- 

 The wood of the firs is usually soft and not durable, so it 

 makes poor lumber. Specimens of the balsam fir will be 

 found here; this is widely distributed over northern North 

 America, and from it is obtained Canada balsam or balm of 



