FREE INSTITUTE OF SCIENCE 
VEGETATION OF SOUTH FLORIDA 
97 
The rainfall at Miami, according to the records of the U. S. Weather 
Bureau, has been for a period of thirteen years, as follows: 
AVERAGE MONTHLY RAINFALL 
JAN. Fes. | Marcu | Арки, | May | June | Jury Avus SEPT. | Ост. Nov. | Dec. ANNUAL 
4 2.5 2d 35 4.5 8.2 Йе) 5.4 9.1 “ae 213 1.6 58.3 
AVERAGE NUMBER OF RAINY DAYS 
4 3 4 4 4 5 8 ч 7 7 2 2 65 
Although the rainfall equals in quantity that of many other regions, yet 
in South Florida, as seen from the figures above, it is unevenly distributed 
throughout the year. The summer season is wet, the winters are usually clear 
and very dry. The conditions then are droughty. During the heaviest rainfall 
of summer, tender crops are beaten to the ground by the pelting force of the 
wind-blown rain, and a hard shower followed by a hot sun does considerable 
mischief. Another ecologic factor of considerable importance in South Florida 
is the wind. The prevailing winds are from the east and despite the fact that 
they blow from the ocean, they are dry winds. Occasional dry hurricanes 
blow from the south and tender vegetation is blackened and parched. The 
effect of the dry hurricane is similar to the desert sirocco of the Mediterranean 
region. 'The influence of these several factors accounts for the xerophytism 
of many South Florida plants. 
Frost is another inhibiting factor. Occasional frosts of short duration 
visit the extreme southern end of Florida, so that tender plants are injured here 
and there. But these slight touches of frost in winter and the cool nights with 
à temperature occasionally near the frost point hardly influence the native 
vegetation of the region. The following is a table of the lowest temperatures 
in degrees Fahrenheit on record at Miami, interesting, especially as to winter 
conditions: 
Jan. | Fes. 
Marca | APRIL May JUNE Jury | Aucust | SEPT. Ост. Nov. Dec. 
. 46° Ba? 65? 69° 60° 62° 54 38° 37 
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We have noted previously that the silver palm, Coccothrinax argentea 
(Plate II, F ig. 3) near Miami is about 1 meter tall, but farther south near Home- 
