SOIL ACIDITY — WHERRY. 267 



Table 9. — Soil reactions of Ericaceae— Continued. 



Note to Table 9. — Several of these Ericaceae were studied by Arrhenius in Sweden, giving the following 

 data: Pyrola secunda, sp. ac. 100 to 10; Arctostaphylos species, sp. ac. 300+ to 1; Vaccinium Vitis-Idaea 

 (typical, varietally distinct from American plant), sp. ac. 1000 to 3+; and Empetrum nigrum, sp. ac. 100 

 to 5. 



CONCLUSION. 



In addition to the studies of plant groups above described, special 

 problems of plant distribution have been investigated from the point 

 of view of soil acidity. It has been found 19 that the vegetation areas 

 of southern New Jersey differ distinctly in the acidity (as well as 

 the salt content) of their soils, and this may well account for the 



19 Correlation between vegetation and soil acidity in southern New Jersey, Proc. Acad. 

 Nat. Sci. Philadelphia, 1920, 113-119. 



