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. The morphology and ecology of roots. 
. The morphology and ecology of leaves. 
. The morphology and ecology of thorns. 
. Climbing organs, and modes of climbing. 
. Symbiosis, other than parasitism. 
At your request, an outline has been prepared for a special 
section in the Museum to illustrate physiological, morphologi- 
cal, and ecological phases of plant life. Such an exhibit 
will possess an especial teaching value, and enhance the use- 
fulness of the museum to teachers, and to classes in nature- 
study and elementary botany. 
Meteorological observations have been continued through- 
out the year as usual. In addition to the records of pre- 
cipitation and of soil- and air-temperatures, instruments for 
measuring the evaporating power of the air were installed on 
June 6, at three different stations. Station 1 was located on 
the dry, rocky, shaded knoll, just west of the propagating- 
houses; station 2 was in the low swampy region about 50 
feet south of the stable; and station 3 was located in the ex- 
periment-garden, about six feet east of the instrument-shel- 
ter. These atmometers were installed and the records 
made in codperation with Dr. Burton E. Livingston, of the 
Desert Botanical Laboratory of the Carnegie Institution, at 
Tucson, Ariz. Dr. Livingston has established in the United 
States a number of similar stations, throughout a wide range 
of latitude, longitude, altitude, and distance from large bodies 
of water, and the comparison of the observations from these 
various stations will doubtless yield valuable information in 
regard to a most important, though as yet inadequately un- 
derstood ecological factor. The results of the observations 
at the Garden show that, for the period between June ro, 
1907 and September 23, 1907, the amount of recorded pre- 
cipitation was .85 inches in excess of the evaporating power 
of the air (loss from the evaporimeter) at the propagating- 
house, and 4.48 inches in excess near the stable, while in the 
experiment-garden the evaporating power of the air was 2.78 
inches in excess of the precipitation recorded. A complete 
wm bo NH 
