STUDIES OF MEXICAN AND CENTRAL AMERICAN 

 PLANTS-NO. 7." 



By J. N. Row, 



INTRODUCTORY NOTES. 



The present number of these studies is confined almost entirely 

 to Mexican plants. The rich collections of E. W. Nelson and E. A. 

 Goldman, C. G. Pringle, E. Palmer, C. A. Purpus, and C. Conzatti 

 have, as in previous reports, furnished most of the new species. In 

 addition to these my own collections, now comprising some 10,000 

 numbers, have been drawn upon. These come from all parts of 

 Mexico, my visits having now been extended to all but four of the 

 twenty-nine States and Territories of that country. 



In 1908 I made my seventh journey to Mexico. Primarily this 

 was not a Mexican expedition, but rather one into the southwestern 

 United States. I had been invited by Dr. D. T. MacDougal, director 

 of the Desert Laboratory, to make a special study of the Cactaceae 

 about Tucson, Arizona, and upon his recommendation a grant from 

 the Carnegie Institution was made to enable me to visit the South- 

 west, making collections in western Texas, New Mexico, Arizona, 

 and southern California. While thus engaged I entered Mexico at 

 three points. At two of these, Nogales, Sonora, and Initial Monument, 

 Lower California, only a short time was spent in collecting plants. 

 Opposite El Paso more time was given to this work. 



On March 30, accompanied by Dr. E. Palmer, the veteran botanical 

 collector, I left El Paso over the Mexican Central Railroad for Chi- 

 huahua City, some 250 miles south of the United States border, and 

 the following day I took train for Miiiaca, located some 250 miles 

 west of Chihuahua City. Here I made a small collection, obtaining 

 two interesting cacti, Opuntia tenuispina and Echinocactus polyacan- 

 ihus, along with various herbs and shrubs. The next day I returned 

 east from Minaca as far as San Antonio, where I took a stage for 

 Cusihuiriachic. From San Antonio the road runs almost directly 

 south over a grassy mesa until within a few miles of the latter place, 

 when it rapidly descends into a deep and narrow ravine. Nearly all 



« Continued from vol. 12, p. 302, of the Contributions. 



