STUDIES OF MEXICAN AND CENTRAL AMERICAN 
PLANTS—NO, 4. 
By J. N. Rose. 
INTRODUCTORY NOTES. 
These studies, continued from page 55 of this volume, consist chiefly 
of descriptions of new Mexican plants, most of which have been on 
hand several years, but a few of which are from collections made 
during the past season. None have been described until all the known 
Mexican species related to them were studied and in most cases a 
synopsis of the genus prepared. So many questions in nomenclature 
require further investigation and so many citations must be verified 
that there are many of our Mexican genera of which it seems impossi- 
ble as yet to present a synopsis. As some of the species described 
below have long been named and distributed to our larger herbaria, it 
is important that these at least should be published. 
Since my last paper of this series was published I have made a fourth 
journey to Mexico, this time in company with Mr. Joseph H. Painter, 
who proved himself a most earnest and valuable assistant. The time 
spent in Mexico was about twoand a half months (August 7 to October 
20, 1903). 
Considerable work was done about the City of Mexico, especially on 
the high mountains which form the rim of the valley of Mexico. From 
here we made excursions, spending several days at Cuernavaca, two- 
at Pachuca, one at Toluca, two at Yautepec, one at Tultenango Canyon, 
and one at Aguas Calientes. A number of these trips were made to 
find long-lost species of Humboldt, Hartweg, and other collectors and 
to look for Crassulaceae and Cacti. On some of these trips I had as 
my companion Mr. C. G. Pringle, whose knowledge of the plants of 
central Mexico made his services most valuable to me. The last of 
August we all moved to Guadalajara, where extensive work was done 
in the great barranca of the Santiago, at Rio Blanco, where Dr. E. 
Palmer collected so many new species in 1887—several days about 
Lake Chapala and one at Etzatlan. At Guadalajara we were joined 
by Mr. E. W. D. Holway, who later accompanied us in the ascent of 
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