206 



EDGAR NELSON TRANSEAU 



other habitat of this vicinity.'^ This corresponds with certain psy- 

 chrometer and thermometer readings in which it was found that 

 during the hottest part of the summer the lowest relative humidity 

 and the highest temperatures were also recorded in this associa- 

 tion. As shown by thermograph records made during May, 

 June, and July, 1907, the soil surface temperatures vary during a 

 day from 20° to 40°F. This is somewhat less than the variation 

 on the exposed beaches, but greater than the variation in the fresh 

 water marsh and the upland associations. At a depth of 1 foot 



Fig. 7. The Ammophila Association of the Upper Beach on East Beach, north 

 of Northport. 



the soil temperatures show no diurnal deviations. In the salt 

 marsh near the Carnegie Station the salt content of the water in 

 the Spartina cynosuroides Association is similar to that of the 

 open harbor. Counting this as 100 per cent there is a steady 

 decrease in salt content as we go toward dry land. At the tension 

 line between this and the Spartina-patens Association the average 

 salt content of the soil water is 85 per cent. About the middle 

 of the Spartina-patens Association this is reduced to 76 per cent. 



^ Transeau, Edgar N. The Relation of Plant Societies to Evaporation. Bot. 

 Gaz. 45: 217-231. 1908. 



