1922] JOHNSTON—PEACH BUDS 315 
temperature data obtained during the last three years (1919-1921) 
at the Maryland Station. The 1919 data include those previously 
reported by JoHNnsTOoN.’ Fifteen Elberta and fifteen Greensboro 
trees are averaged for this year’s data. The 1920 data have not 
yet been reported, but are the averages of twenty-seven trees, 
representing eighteen varieties. The buds of this year were col- 
lected from an orchard that had been severely pruned the year 
previous. The 1921 data are very meager, having been obtained 
from two trees only, one an Elberta, the other a Greensboro. 
Moisture determinations, however, were made more frequently 
during this year. 
Temperature evaluations 
Three kinds of temperature indices have been applied to these 
moisture data. In making use of the remainder indices, it is 
TABLE I 
MOISTURE CONTENT OF PEACH BUDS WITH sg melee TEMPERATURE 
INDICES SUMMED FROM JANUARY I OF EACH 
MoOIsTURE TEMPERATURE INDICES SUMMED FROM JANUARY I 
Date Ratio of water Dail ae . 
ly mean Physiological Exponential 
content to ar | above 43°F. index index 
19 
SRAE Fe 0.69 14 12.6 2.9 
POOIORSY Foon is 0.85 22 37.3 16.16 
March 9.5 1.61 86.2 31.31 
ASIC 88 oi gee es 3.65 173 218.8 59.83 
1920 
OUGARY 90. er 0.73 ° 2.5 1.00 
MSD Fo 0.77 ° 10.3 5.16 
DEAtCh 99s Bk 1.40 48 66.5 18.86 
BOE Oe A eee 147 177.0 36.22 
g2i 
SOMUAtY O00) ace: 0.86 32 36.4 11.47 
ODIGAIY 390s 0.99 37 51.0 18.14 
POpreary 16-00%. cs 1.33 65 85.0 24.19 
Peasy #8. ie 1.16 65 85.3 24.19 
BRC Fo ese 1.46 120.7 32.56 
Maren S60 2.27 185 252.3 45.10 
MAK a ae. 2.72 223 294.0 50.67 
assumed that 43°F. (6.1° C.) is the “zero” for growth and other 
physiological processes, and that daily mean temperatures above 
3Jo ee Eart S., An index of hardiness in peach buds. Amer. Jour. Bot. 
2373-379. 
