6 MISSOURI BOTANICAL GARDEN BULLETIN 
consequent damage to plants both indoors and out. Follow- 
ing an unprecedentedly warm March, with all vegetation 
at an unusually advanced stage, a freeze in early April 
resulted in the destruction or setting back of some of our 
choicest plantations. Many of the largest and finest shrubs 
had to be cut back to the ground and the damage to the 
roses was not overcome during the season. Trees 20 and 30 
years old were so badly injured by the freeze that they had 
to be cut down, and it will be many years before certain 
spots in the Garden can be brought back to their former con- 
dition. Quite as disastrous as the freeze to outdoor plants 
was the prolonged high temperature of the summer to the 
plants under glass. Certainly not since the erection of the 
new conservatory has the effect of the hot weather been so 
serious. Although the temperature has been higher for short 
periods in preceding years, no such duration of heat has, 
according to the weather reports, been equalled within the 
last fifty years. Whereas in previous summers the shading 
of the houses was not necessary more than once or twice 
during the season, during the summer of 1921 the shading 
was applied six or seven times, both on the roofs and sides 
of the houses. Overhead spraying and watering was resorted 
to whenever possible, in order to lower the temperature. In 
spite of every precaution, the orchids and other tropical 
plants burned badly. While apparently no permanent injury 
has resulted, it required much extra work on the part of the 
gardeners to prevent the loss of some of our finest specimens 
and the blooming of the orchids in particular was seriously 
affected. It is difficult for those visiting the Garden from 
other parts of the country to appreciate the weather condi- 
tions with which we have to contend in St. Louis in order 
to bring various collections to a state which will make possi- 
ble favorable comparison with similar collections elsewhere. 
Quite apart from the extremes of heat and cold to which 
plants are sometimes subjected, the uncertainty of the suc- 
ceeding season adds to the difficulty of definitely planning 
certain exhibits. The fact that within the past ten years 
we have had summers varying in amount of rainfall from 
three-quarters of an inch to forty-five inches within the 
same period explains why the Garden is so limited in the 
plants which may be used for floral displays out of doors. 
Tests of plant materials from all parts of the world could 
formerly be made in the hope of securing new and attractive 
