Vol. 9, No. 2 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN August 1, 1955 



REVISION OF THE GENUS SAGITTARIA 

 ( ALISMATACE AE ) l 



Clifford Bogin 

 introduction 



The genus Sagittaria is one of approximately ten that comprise the family 

 Alismataceae. This family is one of a series of related primitive monocotyledonous 

 groups which include the bulk of aquatic angiosperms. The entire complex is 

 interesting from the standpoint of phylogenetic origins and relationships, dis- 

 tributional patterns, ecology, and vegetative variability. The inherent diversity in 

 leaf-shape as well as the wide distribution of Sagittaria has resulted in a con- 

 fused taxonomy that is greatly in need of study. The frequency of the genus in 

 eastern North America has made it a familiar sight to anyone who is interested 

 in plants in general and aquatic plants in particular, while its various morpholog- 

 ical responses to its environment have always been a striking feature and a source 

 of conjecture to the writer. The opportunity to investigate the genus critically was 

 therefore greatly welcomed. Such research could profitably be undertaken at The 

 New York Botanical Garden since large and varied collections were on deposit 

 there, while several indigenous species found in the vicinity could be studied 

 during their entire growing period. 



Sagittaria, or arrowhead, as here treated, consists of 20 species, mostly Amer- 

 ican, that grow in a diversity of paludal and aquatic habitats. It is predominantly 

 a genus of swamps or quiet shallow fresh-water, but it is also found in deep 

 waters of streams and in tidal brackish waters. While mainly a genus of the warm- 

 temperate latitudes, several species are purely tropical in distribution, and others 

 range nearly to the Arctic Circle. 



In addition to the collections in the herbarium of The New York Botanical 

 Garden, other principal collections of the genus were borrowed or visited. Al- 

 together more than 8000 specimens were examined critically. Those herbaria 

 whose collections contributed to this study are listed below with their standard 

 abbreviations as suggested by Lanjouw & Stafleu (1952). 



A — Arnold Arboretum, Cambridge, Massachusetts. 

 GH — Gray Herbarium of Harvard University, Cambridge, Massachusetts. 

 IA — State University of Iowa, Iowa City, Iowa. 



K — Royal Botanic Gardens, Kew, England. 



L — Rijksherbarium, Leiden, Netherlands. 

 LIL — Instituto Miguel Lillo, Tucuman, Argentina. 



MEX — Museo Nacional de Historia Natural de Mexico, Mexico, D. F., Mexico. 

 MO — Missouri Botanical Garden, St. Louis, Missouri. 

 NY — The New York Botanical Garden, New York, N. Y. 

 UC — Herbarium of the University of California, Berkeley, California. 

 US — United States National Herbarium, Smithsonian Institution, Washington, D. C. 



The author wishes to thank the directors and curators of these institutions 

 from which material was borrowed. He also gratefully acknowledges the consid- 

 erate and considerable assistance of the following persons: Dr. D. D. Keck, under 

 whose direction and guidance most of this research was conducted and who so 



Submitted in partial fulfillment of the requirements of the Degree of Doctor of Philos- 

 ophy in the Faculty of Pure Science, Columbia University. 



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