316 BOTANICAL GAZETTE [NOVEMBER 
43° are ‘‘effective” units. These daily mean temperatures (average 
of daily maximum and minimum) above 43° have been summed 
from January 1 to each date on which the moisture determinations 
were made. ‘The physiological summation indices, as derived by 
LIvINGsTON,’ were obtained from the daily mean temperatures, 
i i A 
0 50 106 150 200 
REMAINOER INDICES 
$ «. PO a 2 cag a ge bea PR Re 1 SR Rae MEE ed 
Fic. t. I g 
from January 1 for years 1919-1921. 
and are likewise summed from January 1 to each particular date. 
The chemical efficiency indices proposed by Livincston and 
LIVINGSTON’ were summed from the indices corresponding to the 
daily mean temperatures. These three kinds of temperature 
indices are presented, together with the moisture data, in table I. 
4Livincston, B. E., Physiological temperature indices for the study of plant 
growth in relation to climatic conditions. Physiol. Res. 1:399-420. 1916. 
5 Livincston, B. E., and Lrvineston, G. J., Temperature coefficients in plant 
geography and climatology. Bor. Gaz. 56:349-375. 1913. 
