﻿Nichols: The vegetation of Connecticut 191 



while many ponds have become completely clogged up through 

 the accumulation of muck or peat, there are others in which scarcely 

 any such accumulation would appear to have taken place. And 

 between these two extremes are ponds which exhibit various 

 intermediate degrees of filling. Although the reason for this 

 discrepancy between different ponds is not clear at the present 

 time, it may be due merely to the chance failure of certain plants to 

 become established in the " barren " lakes as soon as in the "fertile" 

 ones. Or it is quite conceivable that a paucity of organic debris 

 may be due to the existence of environmental conditions unfavor- 

 able to the luxuriant development of aquatic plants. Certain it 

 is that in ponds with a sandy, gravelly, or rocky bottom, i. e., 

 in ponds where muck or peat has failed to accumulate, the 

 vegetation invariably is sparser than in ponds with a mucky 

 bottom. Particularly is there a dearth here of those species most 

 active in peat formation, such as the larger pondweeds, the water- 

 lilies, the pickerel-weed, and the cat-tail. The vegetation along 

 the sandy or gravelly shores of such a pond is quite different 

 from that along mucky shores. Representative species are Erio- 

 caulon septangulare, Najasflexilis, and Lobelia Dortmanna — growing 

 in shallow water; and Panicum agrostoides, Cyperus dentatus, 

 Cyperus strigosus, Eleocharis acicularis, Juncus brevicaudatus, 

 Hypericum mutilum, Lysimachia terrestris, Gratiola aurea, and 

 Gnaphalium uliginosum — growing on the shore. The factors 

 directly or indirectly responsible for the assumed adverse envi- 

 ronmental conditions referred to above may possibly be many. 

 Among those that may enter in are the depth of the water body, 

 the temperature and clearness of the water, the steepness of the 

 shores, the amount of inorganic detritus washed in by streams or 

 otherwise, and the source of water supply. That the degree of pro- 

 tection from or exposure to wind, and the nature of the water 

 currents may also be important factors is suggested by the fact 

 that mucky and sandy shores often occur around the margin of 

 the same lake, the former in the more sheltered, the latter in the 

 more exposed situations. Failure of peat to accumulate might also 

 of course result from any conditions which would promote rapid 

 and complete decomposition ; or locally it might be effected through 

 the removal of plant remains by water currents. 



