LONG ISLAND VEGETATION 



209 



vated ridge with its steep slope toward the sound. The evapora- 

 tion is less than that of the salt marsh by 25 per cent. The domi- 

 nant plants are Anirnophila arenaria, Lathyrus maritimus, and 

 SoJidago sempervirens. These plants make up an unusually large 

 part of the vegetation. The scattered secondary species are 

 numerous, of which the most common are: Oenothera biennis, 

 Cyperus grayi, Salsola kali, Atriplex patula hastata, Strophostyles 

 helvola, Artemisia caudata, Dondia maritima, Chenopodium album, 

 Rhus radicans, Oenothera oakesiana, Bidens bipinnata, Pluchea 

 camphorata, and Lactuca canadensis. 



On the bars and spits the further development of this formation 

 leads to the establishment of the Prunus-maritima Association. 

 At the bases of the headlands the upper beach is constantly 

 invaded by the clay, sand, and gravel brought down from above by 

 various agencies of erosion. The Ammophila Association is here 

 succeeded by the pioneer association of the cliffs. \\Tiere the 

 upper beach is extensive and dune formation occurs another set of 

 associations is developed. All of these associations are so closely 

 allied to the forest successions that they will be discussed in that 

 connection. The object of this paper has been mainly to show the 

 trend of the marine successions on northern Long Island, hence 

 no attempt has been made to discuss the literature bearing on the 

 causes of the successions or the plant associations that have been 

 distinguished on neighboring coasts. By way of summary a dia- 

 gram of the various successions is given in figure 8. 



