Bogs, Their Nature and Origix. 



57 



such vegetation one must wade knee-deep to reach the quaking 

 bog (Qb), where the peat mosses occur in almost pure growth, 

 but supporting fine pitcher plants (Sarracenia purpurea), patches 

 of cranberry, cotton grass (Eriophorum zirginicum) (V) and 

 Scheuchzeria palustris. The uniform surface of the bog is broken 

 bv a tree island (Figure 3, TI). The small trees and shrubs 

 found surrounded by the peat mosses are black spruce, red 

 maple (M), cherry birch (Betula lenta), white birch, rhodora (#), 

 high bush blueberry (o), sheep laurel (Kalmia angusti folia), 

 white swamp azalea, steeple bush and leather-leaf. Green- 

 leaved pitcher plants occur in the sphagnum beds beneath the 

 trees. Between this clump of trees and the elevated, tree- 

 covered, dry ground beyond the bog, occasional larch and pitch 

 pine trees have invaded the bog. The first year's observations 

 (1903) showed relatively few trees on the surface of the bog 

 proper, but in the last season (1908) the writer counted a num- 

 ber of white birch trees which had invaded the bog from the 

 north side of the tree island (Figure 3, TI, B) together with 

 clumps of mountain holly, red maple and cinnamon ierr\(Osmunda 

 cinnamomea) . The continuity of the bog surface is also broken 

 by large patches of leather-leaf (++) which at first were isolated 

 from each other by considerable intervals of open bog, but 

 during the five years that have elapsed since the first observa- 

 tions were made, these gaps have closed and many smaller 

 associations of leather-leaf have united. This encroachment 

 of the shrubby leather-leaf, so as to surround and enclose large 

 areas of open bog, is especially noticeable in the center of the 

 bog (Cb), where the pitcher plant grows together with the 

 sundew (Drosera rotundijolia) , sedge (Carcx bullata) and cran- 

 berry. Here and there between the Cassandra bushes one 

 notices patches of a pure cranberry growth (C). The pale 

 laurel swamp loosestrife (Lysimachia stricta) and cotton grass 

 (Eriophorum virginicum) (V) are scattered amongst the sedges 

 and leather-leaf shrubs over the surface of the bog. At the 

 edge of the bog in the southwest and northwest angles occur 

 clumps of the white swamp azalea. 



The stream issuing from Lost Pond is lined by thickets 

 composed of red maple, white birch, mountain holly, choke- 

 berry, white swamp azalea, black alder (Ilex verticillata) , leather- 

 leaf, service-berry (Amelanchier canadensis), witch hazel (Ha- 



