GEOGRAPHICAL DISTRIBUTION 



159 



is struck by the appearance of the firs and spruces, which 

 gradually become more and more dwarfish, at length ris- 

 ing but a few feet from the ground, the branches spread- 

 ing out horizontally many feet and becoming thickly inter- 

 woven. These present a comparatively dense upper 



FIG. 74. Lapland rhododendron (Rhododendron lapponicum). Photo- 

 graphed on the summit of Mt. Madison, New Hampshire, June 25, 1917,' 

 by Ralph E. Cleland. 



surface, which is often firm enough to walk upon. At 

 length these disappear wholly, and give place to the Lap- 

 land rhododendron (Fig. 74), Labrador tea, dwarf birch, 

 and alpine willows, all of which, after rising a few inches 

 above the ground, spread out over the surface of the 



