PREFACE. 



Tlie present volume consists of an account of the trees and shrubs 

 of Mexico, by Mr. Paul C. Standley, Associate Curator of the United 

 States National Herbarium. The work is based wholly upon the 

 extensive series of Mexican plants in the National Herbarium, a 

 large proportion of which have been obtained by special investigators 

 sent out by the United States National Museum and the United 

 States Department of Agriculture. The flora of Mexico, especially 

 the arborescent flora, includes many species of great economic value. 

 They furnish many products of commercial importance, such as 

 henequen and ixtle fiber, palm oil, lumber, cacao, rubber, drugs, 

 alcohol, and many fruits. 



Heretofore no descriptive flora of any portion of tropical conti- 

 nental North America has been published, and the identification of 

 the species of plants yielding important products has often been 

 very difficult. Identification of material has been possible only by 

 comparison with extensive series of herbarium specimens, such as 

 are to be found only in the larger botanical institutions, or by reference 

 to isolated descriptions, many of them available only in the largest 

 fibraries. The present work brings together all the published species 

 of woody Mexican plants and furnishes keys for their identification 

 as well as brief descriptive notes. Much information is presented 

 also concerning commercial and local uses of the plants. The ver- 

 nacular names of the trees and shrubs are given, and since these are 

 fairly well standardized by local usage they will be found helpful as 

 guides to the identity of fragmentary or otherwise difficult material. 



Several collaborators have aided in the preparation of this volmne 

 by contributing the accounts of certain groups in which they are 

 particularly interested, as follows: Dr. William R. Maxon, Gleichen- 

 iaceae and Cyatheaceae; Dr. A. S. Hitchcock, Poaceae; Dr. William 

 Trelease, Agave and Quercus; Dr. S. F. Blake, Meliaceae, Polyga- 

 laceae, Violaceae, and Asteraceae; Mr. Ellsworth P. Killip, Passi- 

 floraceae; Dr. N. L. Britton and Dr. J. N. Rose, Cactaceae; Dr. B. L. 

 Robinson, Eupatorium and Opliryosporus; Dr. J. M. Greenman, 

 Senecio. 



Frederick V. Coville, 

 Curator of the United States National Herbarium. 



