LONG ISLAND VEGETATION 



205 



Lathyrus maritimus has invaded this belt from above. Else- 

 where Daucus carota, Bidens bipinnata, Lactuca canadensis, Rumex 

 acetosella, and Oenothera oakesiana are locally abundant. All 

 these plants are annuals, or are in their first year stage. Aside 

 from the two exceptions noted above all have arisen from seed. 



THE PROTECTED MIDDLE BEACH 



The Salt Marsh Formation. The Spartina-patens Associa- 

 tion. Just below the mean high tide line in the salt marsh as 

 one follows the succession from open water to dry land there is usu- 

 ally an abrupt change in the height of the vegetation. On the 

 outer side of this line is Spartina cynosuroides a meter or more in 

 height ; on the landward side Spartina patens, less than half a meter 

 in height dominates. Where the salt marsh is well developed 

 there is also a rather abrupt change in the slope of the substratum 

 at this same line. The soil is usually peat underlaid with sand 

 or gravel. Spartina patens is usually the dominant plant of the 

 association, as in the salt marsh near the Station for Experimental 

 Evolution. But its dominance may be interrupted by Distichlis 

 spicata, as at the west end of Lloyds Harbor and in the extensive 

 marsh on the southeast side of Lloyds Neck. The secondary 

 species are Salicornia amhigua (fig. 5), S. europaea, Juncus gerardi, 

 Atriplex patula hastata, Plantago maritima, and Limonium caro- 

 linianum. In the autumn the Salicornia becomes conspicuous 

 through its briliant red coloring. 



The Juncus-gerardi Association. At a slightly higher level 

 in the salt marsh Juncus gerardi becomes dominant and the 

 Spartina patens is reduced to second place. Although these two 

 plants have so nearly the same requirements as to be nearly always 

 found together, the slight difference made by a change in level of 

 a few centimeters shows in their relative abundance. The 

 associated species are Gerardia maritima, Solidago sempervirens, 

 Aster tenuifolius, Distichlis spicata, Pluchea camphorata, Triglochin 

 maritima, and Eleocharis rostellata. 



As I have shown elsewhere the rate of evaporation at the outer 

 edge of the Spartina-patens Association is greater than in any 



THE PLANT WORLD, VOL. 16, NO. 7, JULY, 1913 



