Bogs, Their Nature and Origin. 



53 



such areas the successful vegetable forms are those with rela- 

 tively high osmotic pressures in their tissues. In the case of 

 such plants water will enter the root system from soil solutions 

 so strong that the roots of ordinary plants might even function 

 backward and give up water to the soil. 



In view of the exceedingly meagre knowledge which we 

 possess in regard to the details of the general principles above 

 touched upon, it is sincerely to be hoped that botanists will 

 in the future devote more attention to the soil than has been 

 their wont in the past. 



BOGS, THEIR NATURE AND ORIGIN. 



By John W. Harshberger. 



(Continued from February number.) 



The conversion of lakes into bogs has been studied by the 

 writer for several successive seasons on the Pocono Plateau, 

 Monroe County, Pennsylvania. The lakes known as Half Moon 

 Pond and Lost Pond, as well as several sphagnum bogs in glacial 

 kettle holes, are all surrounded by the material which consti- 

 tutes the great terminal moraine. Half Moon Pond is an open 

 body of water about a quarter of a mile long, two hundred 

 yards wide and somewhat crescent-shaped. It is undergoing, 

 however, rapid changes which will convert it into the present 

 form of Lost Pond, while the kettle holes are filled with bogs, 

 partially dry in summer, some with open treeless areas, others 

 completely captured by tree species. The accompanying dia- 

 grams will illustrate the stages through which a lake basin 

 passes in its conversion into a bog by the encroachment of various 

 plants. An examination of the diagrams, illustrating Half 

 Moon Pond (Figures 1 and 2), shows that the surface of the lake 

 is covered with patches (A) of the large yellow spatter-dock 

 (Nymphaea ad-vend). This plant is slowly, but surely, covering 

 the lake surface with its large floating leaves. The central 

 lagoon is surrounded by a fringe of sphagnum moss, the margin 

 of which extends outward in a floating mass (mo). The inner 

 edge is anchored fast to the bottom, but one sinks knee-deep in 

 the spongy mass. In this circumarea of sphagnum grow the 



