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104 MISSOURI BOTANICAL GARDEN. 
April (U.S. Dept. Agr., Weather Bur., Monthly Metr. Sum- 
mary for Saint Louis, Mo., March and April, 1910) :-— 
“The weather for March was very unusual. The mean temperature 
was 57.5°, which is 3.2° higher than for any previous March, and the 
temperature was continuously above the normal, except on the 9th, 
10th, 14th, and 15th. The maximum temperature for the month was 
87, and this has been exceeded but once in March in the history of 
the station. Freezing temperatures occurred on three days only. The 
precipitation was the lowest ever recorded for March, and only twice 
in forty years has a smaller amount been recorded for any month. 
The number of clear days, 22, is the highest ever observed in March, 
and the number of cloudy days, 2, the lowest. The sunshine was 
79 per cent of the possible amount, and was the greatest for March 
since the records began. During the latter part of the month the 
atmosphere was very hazy, causing the sun and the moon to appear 
very red. The wind movement, while not the least for any March, 
was much below the average, and a less amount has been recorded five 
times only in March.” 
and for April :— 
“The temperature for April averaged slightly below the normal 
and was characterized by great extremes, the maximum being sur- 
passed but once in the history of the station. The minimum, while 
not the least for any April, was unusual for the last decade of the 
month. All previous low temperatures have been recorded in the first 
half of the month. The minimum of 25° on the 24th was the lowest 
minimum after the 20th in 74 years. The low temperature was caused 
by a slow movement of a storm area from Illinois to lower Michigan 
that developed in intensity and brought down cold air from the north- 
west. The mean temperature for April was 1.7° lower than that of 
Mareh. A similar case occurred in April, 1907, when the mean 
temperature for April was 5.9° lower than March. The snowfall was 
the heaviest for any April, but never before has so great an amount 
fallen as late as the 24th of the month.” 
The location of the Garden on a high point of land, 
with well-drained areas sloping toward the west and north- 
west, makes damage from the average frost not a very com- 
mon occurrence. Ground frost and consequent damage to 
tender herbaceous plants sometimes occurs, but often when 
frost has been known to occur on the ground, there has 
not been any noticeable effect on the leaves or flowers of 
trees and shrubs. The Garden is also slightly favored in 
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