208 AMERICAN JOURNAL OF BOTANY [Vol. 9, 
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Fig. I. Mean hourly temperatures for January at Pomona, California (field station), 
1919 and 1920; Brooksville, Florida (field station), 1919 and 1921; Los Angeles, California 
(city station), 1919 and 1920; and Tampa, Florida (city station), 1910 and 1919. 
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I I 
/ 2 3 4 S e 7 S 9 /O // \ / 2 3 4- S 6 7 8 9 /O // \ 
Fig. 2. Mean hourly temperatures for February at stations listed under figure i. 
