PREFACE. 
The accompanying report by Dr. J. N. Rose is a continuation of his 
Studies of Mexican and Central American Plants. It varies little in 
style and treatment from the earlier numbers, of which five have 
already been published. ‘They all emphasize the botanical richness of 
the countries south of the United States, and the importance of careful 
work by experienced collectors. 
FREDERICK V. CovILLE, 
Curator of the United States National Herbarium. 
III 
