THE PLANT WOKLD 27 



ou tlieir exposed upper faces covered with a lichen, Umhilicaria sp., 

 while patches of hair moss, Polytricluim commune, are found here and 

 there throughout the woods. 



Several well marked belts of vegetation can be delimited on the 

 mountain side : (1.) the belt of lowland timber extending, as shown in 

 the figure 1, half way up the southern slopes of Mount Ktaadn. These 

 trees approach, more and more, a xerophytic condition, as the elevation 

 increases, until approximately an elevation of 3,000 feet is reached, when 

 the belt of normal sized trees gives way to the pucker-bush. This forest 

 consists of five or six dominant trees, Picea nigra Link, Betulapapyrifera 

 Marshall, Betida lufea Michx. f., Pyrus Americana D. C, Abies halsamea 

 Mill., Acer rubrum L., and Acer spicafum Lam., with thickets of Alrius 

 viricUs D. C, growing on the Slide. (2.) The belt of stunted trees, the 

 pucker-bush (11.) extends to an elevation of about 3,700 feet. It consists 

 largely of ancient black spruce trees {Picea nigra), that have battled 

 with the elements for years, assuming, therefore, a striking xerophytic 

 habit. Thoreau, in his "Maine Woods," p. 81, describes his impression 

 of this region of the mountain side in the following fine description : 

 "At first scrambling on all fours over the tops of ancient black spruce 

 trees, old as the flood, from two to ten or twelve feet in height, their 

 tops fiat and spreading and their foliage blue and nipped with cold, as 

 if for centuries they had ceased growing upward against the bleak sky, 

 the solid cold, I walked some good rods erect upon the tops of these 

 trees, which were overgrown with moss and mountain cranberries. It 

 seemed that in the course of time they had filled up the intervals between 

 the huge rocks, and the cold wind had uniformly leveled all over. Here 

 the principle of vegetation was hard put to it. There was apparently a 

 belt of this kind running quite around the mountain, though, perhaps, 

 nowhere so remarkable as here. Once slumping through, I looked 

 down ten feet, into a dark cavernous region, and saw the stem of a 

 spruce, on whose top I stood, as on a mass of coarse basket work, fully 

 nine inches in diameter at the ground." Mountain ashes and alders also 

 grew in association with the black spruces of the pucker-bush. Spar- 

 ingly on the Slide in this belt were found Cornus Canadensis L., Poten- 

 tilla tridentafa Ait., Spiraea salicifoUa L., Empetrum nigrum L., and 

 Ledum latifoUuni Ait. (3.) The belt above timber line (III.), extending 

 across the confused mass of granitic boulders up to the rim of the table- 

 land and mountain summit, is crossed next with but few plants to 

 reward the botanist. (4.) The upper stretches of the mountain, includ- 

 ing the alpine garden on the table-land and the immediate summit of 

 the mountain, forms the alpine belt of Mt. Ktaadn. To it are restricted 

 the true alpine plants found hj the writer in making the ascent from 

 the south and precipitous side. Among the rocks of the table-land and 



