[From the Bulletin of the Torrey Botanical Club, 43: 235-238, 18 Je 1916 J 



The vegetation of Connecticut 

 V. Plant societies along rivers and streams* 



George E. Nichols 

 (with eleven text figures) 



In the present series of papers on the vegetation of Con- 

 necticut, the principle of succession has been adopted as the most 

 satisfactory basis for classifying plant associations. This scheme 

 of classification, it may here again be remarked, treats vegetation 

 both from a genetic and a dynamic standpoint. It recognizes the 

 fact that plant societies, or associations, as they exist today, are 

 the product not alone of contemporaneous conditions, but of past 

 conditions as well. It also emphasizes the fact that the plant 

 associations of today are not necessarily permanent, but are liable 

 to change through the influence of various factors. 



In the third and fourth papers of the series, f attention was 

 directed to the plant associations of uplands and of lowlands. 

 There the changes in vegetation, and therefore the succession of 

 plant associations, are influenced primarily by plant and animal 

 agencies — in other words, by biotic factors. There remain to be 

 considered, then, successions which are associated not only with 

 biotic factors but with topographic factors as well. Succession of 

 this sort has been termed Topographic Succession. Topo- 

 graphic succession is seen principally along rivers and streams 

 and along the coast. The present paper deals with plant soci- 

 eties along rivers and streams. Some of these societies might 

 almost equally well have been treated along with the societies of 

 uplands and of lowlands; yet, on the whole, so marked may be the 

 impress of a stream on the vegetation at its margin, and so closely 

 linked may be the development of the one with that of the other 

 that the two cannot well be treated separately. 



* Contribution from the Osborn Botanical Laboratory. 



tTorreyai4: 167-194. 1914; Bull. Torrey Club 42: 169-217. 1915. 



235 



