90 
R. H. Forbes of the Experiment Station, for many courtesies 
and for the privilege of taking specimens from this collection that 
could not be obtained elsewhere. 
Professor J. J. Thornber, Botanist to the Experiment Station, 
gave every assistance in the examination of this material, and 
on surveying tours of the surrounding country. Arrangements 
were completed with the University by which a set of plants col- 
lected by myself in the northern part of Arizona in 1898 were 
presented to the herbarium in exchange for material to be for- 
warded to the Garden from time to time. 
It being my purpose to make an examination of the flora of 
this arid region from several points in order to select the best 
place for securing and shipping specimens before any actual col- 
lection was made, I proceeded to Nogales, Arizona, and to Guay- 
Fic. Island in Bay of eee bearing numbers of a large Cereus (see 
Fig. - ae fringed with mangroves 
“mas in southern Sonora. The last named place is a town of 
about eight thousand inhabitants situated upon the bay of the 
same name, which is an arm of the Gulf of California. 
The surrounding country is extremely dry and as the place is 
only 28 degrees north latitude the climate is extremely warm 
even during the winter months, and the vegetation is highly 
xerophytic. 
Minor mountain ridges extend to within a short distance of 
the actual shore line, and the “ Saguaro” or tree cactus (Cereus 
