THE ALLIONIACEAE OF MEXICO AND CENTRAL 



AMERICA. 



By Paul C. Standley. 



INTRODUCTION. 



Only a short time has passed since the writer, at that time con- 

 nected with the Agricultural College of New Mexico, published a 

 paper upon the Allioniaceae of the United States with notes on 

 Mexican species a , but since that time he has had access to a large 

 amount of material not then available. The Mexican and Central 

 American collections in the National Herbarium were not included 

 in those loaned him for study in the preparation of the earlier paper. 

 These specimens are essential to a proper understanding of the 

 southern members of the family, including as they do the extensive 

 collections made in the region by Rose, Nelson, Goldman, Conzatti, 

 Pittier, Tonduz, and many others that are not fully represented else- 

 where. In addition it has been possible to examine all the material 

 in the Gray Herbarium and in the herbaria of the New York Botanical 

 Garden and Columbia College, Capt. John Donnell Smith, Dr. E. L. 

 Greene, the Academy of Natural Science of Philadelphia, the Arnold 

 Arboretum, and the University of Pennsylvania. These collections 

 include a great many historic specimens, especially the Gray Herba- 

 rium, where are found the types of the many species described by 

 Gray and Watson. Although supposed duplicate type specimens of 

 most of the species had been seen, it was impossible to be absolutely 

 certain upon some points without examining the actual types. Some 

 of the collections in the herbarium of the New York Botanical 

 Garden are particularly valuable in the study of any Mexican group, 

 and the Panama plants collected by Sutton Hayes, most fully repre- 

 sented there, added several new members of the Allioniaceae to our 

 North American flora, notably the genus Colignonia. 



When the earlier paper was published the material accessible was 

 not sufficient to warrant the study of certain tropical genera sucli 

 as Neea and Pisonia, which are treated here for the first time from 

 the standpoint of Mexico and Central America. 



oContr. Nat. Herb. 12:303-389. pi. 28-4$. f. 49-67. 1909. 



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