172 
November 12 (subject to be announced later), by Dr. H. M. 
Richards. 
November 1g (subject to be announced later), by Dr. D, T. 
MacDougal. 
A VISIT TO THE DESERT BOTANICAL 
LABORATORY 
During the present summer I have had the privilege of spend- 
ing two months in research at the Desert Botanical Laboratory 
of the Carnegie Institution, at Tucson. I take this opportunity 
of presenting a brief account of my visit, and of the laboratory 
and its surroundings. 
I arrived at Tucson, in company with Professor Hugo de 
Vries, on the evening of June 20, being met and escorted to the 
hotel by Dr. W. A. Cannon, Resident Investigator, in whose 
immediate charge the ieee stands. The two days follow- 
ing, comprising Professor de Vries’ visit to Tucson, were spent 
in a general reconnaisance of the region. We were able during 
this brief period, to visit the Laboratory and examine the vegeta- 
tion of the hill upon which it is situated, and to drive over: 
considerable extent of the mesa in three directions. At the close 
of Professor de Vries’ visit, I established myself at the laboratory, 
and began my work 
The building is situated upon the gentler northern slope of a 
hill of volcanic rock, overlooking the valley of the Santa Cruz, 
some two miles from the town of Tucson. The soil is a fine 
adobe, or clay, with a very generous admixture of stones and 
boulders. The saree of the range of hills and mountains, 
of which the laboratory hill is an outpost, is in general that of 
all the rocky hills and ridges which one sees from the train 
between El! Paso and Tucson, with the difference, however, that 
the saguara or giant cactus (Cereus giganteus)is a strong element 
which is lacking in the more easterly situations. On the other 
hand, one misses the agave and yucca. Yet the vegetation is 
rich in desert types, of a vigorous growth, and affords 
abundant material for investigation. 
