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AMERICAN JOURNAL OF BOTANY 
[Vol. 9, 
to the difference in the prevalence of the two fungi. Though the writer 
is responsible for the views on the relation of weather conditions to fungous 
growth here presented, he has received much assistance in the compilation 
and interpretation of weather data from the meteorologists in charge of the 
U. S. Weather Bureau stations nearest the regions discussed, W. J. Bennett 
of Tampa and H. B. Hersey of Los Angeles. 
In comparing the climatic conditions of the strawberry -growing regions 
of central Florida and southern California, it is necessary to make use, in 
part, of the meteorological data from Tampa and Los Angeles. These 
data are, of course, not entirely representative of conditions in the straw- 
berry fields, since the stations are located in cities. The two stations are, 
however, about equally distant from the strawberry-growing areas, and 
bear somewhat the same relation to them. Moreover, good thermograph 
records are available from field stations at relatively short distances from 
the strawberry regions, and these have been used in comparing temperature 
conditions. At least the weather data here used represent conditions in 
the strawberry fields with a degree of accuracy well within the limit of 
error of such field observations as are here recorded. 
Moisture Conditions 
The prevalence of Botrytis on strawberry fruits in semi-arid southern 
California was surprising in view of the fact that in the southeastern states 
it has been repeatedly observed (lo, p. 8) that abundance of Botrytis on 
strawberries was closely associated with excessive precipitation. The mean 
annual precipitation at Tampa (4940 inches) is much greater than that of 
Los Angeles (i 5.62 inches). The period under discussion, however (January 
to April), comes within the "dry season" in Florida and the "rainy season" 
in California. As shown by the Annual Meteorological Summaries for 
1920 published by the two stations (table i), the mean precipitation for 
this period as well as for the month of December is actually greater at 
Los Angeles than at Tampa. 
Table i. Monthly Mean Precipitation , in Inches 
Los Angeles, Cal., Tampa, Fla., 
1877-1920 1890-1920 
December 2.67 2.05 
January 3.34 2.62 
February 3.19 2.75 
March 2.92 2.20 
April 0.89 1.92 
Surface irrigation of strawberries is very rare in Florida but is regularly 
practised in California, a fact which still further increases the amount of 
water actually used on strawberry beds in the latter state while the berries 
are ripening. 
Soils vary greatly in both regions, but in general the strawberry soils 
