LONG ISLAND VEGETATION 



203 



tioii. In the inner harbors and land locked lagoons this associa- 

 tion is the forerunner of the Salt Marsh Formation. Here in the 

 early stages it often covers extensive areas. Besides the grass 

 the only plants of importance are Lilaeopsis lineata, Gracilaria, 

 Fucus, and Ascophyllum. I have already pointed out itssiicces- 

 sional relations to the Eel Grass Formation and the Rockweed 

 Formation. When deposition has raised the soil surface well up 

 toward the high tide line the Spartina cynosuroides dwarfs rapidly 

 and give way to the Spartina patens Association. 



THE MIDDLE BEACH 



This is the playground of the autumn and winter waves. Along 

 exposed shores gradation is so rapid that nothing entirely with- 

 stands the wave action during this period of the year. On October 

 19, 1906, for example, at East Beach a single storm resulted in 

 the deposition of a 6-inch layer of gravel over this portion of 

 the strand. Depending on the direction of the wind with refer- 

 ence to the shore drift, the currents may bring about either ero- 

 sion or deposition. In the inner harbors the result is largely the 

 deposition of the fine materials carried by the sea water and the 

 freshwater streams that enter them. Judging by the examina- 

 tion of salt marsh soils this water borne material is not by any 

 means equal to the organic matter deposited by the vegetation 

 after the level has once been raised to within half a meter of the 

 mean high tide level. 



THE EXPOSED MIDDLE BEACH 



The Xanthium-atriplex Association. There is great diffi- 

 culty in defining this association by the use of two plant names. 

 As is commonly the case in open pioneer associations there is the 

 greatest local diversity in its floral composition. Almost as 

 many minor divisions might be recognized as there are common 

 species. The exposed or dry middle beach is subject to extreme 

 insolation, drought, and high temperatures. ]VIy temperature 

 records go as high as 110°F. for the upper inch of soil and the 

 air. The plants are occasionally subjected to salt spray, although 



