i9o8] T RAN SEAU— PLANT SOCIETIES AND EVAPORATION 



229 



area, the water proved by chemical test to be without a trace of chlorid 



at the next low tide. The vaporimetcr was set up precisely as at 

 Station 11. 



Aug. S-13 

 (a days) 



Amt. evaporation, Station 12 112 .8<^*= 



Amt. evaporation, standard 129 . 7 



Comparative evaporation 86 . 9% 



It might be urged, in connection with the high percentage reading 

 at Station 11, that the result was due to the elevation of the instrument. 

 This cannot be otTered, however, as an explanation of the great 

 difference between Stations 11 and 12. 



The other species of plants found near the station are Eleocharis 



rostellata, Asdepias pulchra, Carex gracilis, Lysimachia kirestris, 



Eupatorium per jolia turn, Hibiscus moschcutos, and Dryopkris tlie- 

 iypicris. 



Station ij, — Fresh-water marsh — a continuation of the 



same 



marsh in which the two preceding stations were located. A road, 

 elevated about 3"^ above the marsh, separates this station from the 

 last. I have no doubt but that this road interferes somewhat with the 

 normal air drainage in its vicinity and may account in part for the low 

 reading at Station 13. This station is sufhciently elevated to be beyond 

 the reach of the highest tides. The vegetation about the instrument 

 consisted of O node a sensihilis, Lysimachia terrestris, J uncus effusus, 

 JJryopteris thelypteris, Lycopus amerkana, Iris versicolor, Epilobium 

 adenocaulon, Asdepias pulchra, Carex hystrkina. Near by grew 

 Acorus calamus, Eupatorium perfoliatum, Impatiens hijlora, Ilysanthes 

 attenuata, Rumex altissimus, Polygonum sagitiatum, Scirpus ameri- 



cana, Myrica carolinensis, etc. 



Aug. 5-1J 

 (8 daj-s) 



cc 



per cent, as 



Amt. evaporation. Station 13 57.0 



Amt. evaporation, standard 129 7 



Comparative evaporation 43 Q% 



compare this record with those obtained simultaneously 

 o stations, we see that there is a further decrease of 40 



taking allowances for the interference with air currents at this ..i^llon, 



be a well-marked 



