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feet, though usually it is only about 50 feet tall. It is a hardy 

 species of slow growth and frequently occurs as a stunted tree, at 

 least, at the higher limits of its range. In some sections it forms 

 extensive forests and is cut for lumber ; elsewhere it occurs in 

 mixture with other species. 



Both the common and botanical names of this species have 

 arisen from a remarkable flexibility of the wood, for a branch of 

 the tree can be bent to any angle without fear of breakage. 



The Limber Pine is a five-needle evergreen and is distinguished 

 from all other five-needle pines, except P. albicaulis and P. pumila, 

 by the fact that its needles are practically without teeth. This, 

 however, can be determined only by the aid of a microscope, for a 

 pine needle may appear perfectly toothless until examined under 

 the lens. In fact, there are only five pines whose needles may be 

 regarded as entire, that is, having no teeth. The two in addition 

 to the three already noted are P. aristata, the Bristlecone Pine, and 

 P. Balfouriana, the Foxtail Pine. The Limber Pine is the only 

 one of these five that is represented in the collection. 



Pin us flexilis, like P. Cembra and P. koraiensis, has wingless 

 seeds, but differs from those two in having dehiscent cones that 

 open upon maturity and liberate the seeds. This character of 

 wingless seeds occurs only in three other pines, which are absent 

 from the collections. Lustrous yellow cones, when present, are a 

 further distinguishing feature of the Limber Pine. 



Beyond all the Limber Pines and at the northern end of this 

 Section are two large dark-colored Austrian Pines, one of which 

 is more to the right. A third stands along the edge of the slope 

 on our right. 



We shall now turn our attention to the remaining trees on the 

 slope to the right. To do so we shall go down to the path, face 

 the slope, and commence with the low evergreen to the extreme 

 left. It is 



Pinus sylvestris var. Watereri, Waterer Pine 



This plant was secured from a nursery under this name. It 

 may, however, be incorrect, for the Waterer Pine is usually of 

 upright columnar habit. 



