Aquatic Vascular Plants of New England: 



Part 5. Araceae, Lemnaceae, Xyridaceae, 



Eriocaulaceae, and Pontederiaceae 



by 

 C. B. Hellquist and G. E. Crow 



INTRODUCTION 



This is the fifth in a series of reports on the aquatic and wetland 

 flora of New England. This long needed treatment has been prepared 

 to aid conservationists, fish and game personnel, consultants, 

 botanists, and students in the identification of aquatic plants. The 

 coverage is strictly New England but is of value throughout the 

 northeast. Data have been gathered from herbaria in New England 

 and from personal field work. 



Chemical data presented represent samples from many waters 

 throughout New England. The alkalinity readings are total alkalinity, 

 expressed as milligrams per liter (mg/1) CaCO^. The number of 

 observations are included in parentheses following alkalinity and pH 

 values. Since pH and alkalinity vary greatly during the day, the values 

 are only indicative of the water quality. Chloride values are given 

 where data are available and of value. 



The rare and endangered plant lists referred to are those prepared 

 for each of the six New England states by the New England Botanical 

 Club in cooperation with the United States Fish and Wildlife Service, 

 Office of Endangered Species, Newton Corner, MA (RI — Church and 

 Champlin, 1978; MA — Coddington and Field, 1978; VT — Countryman, 

 1978; ME — Eastman, 1978; CT — Mehrhoff, 1978; NH — Storks and 

 Crow, 1978). Taxa indicated as rare, threatened, or endangered for the 

 entire New England Region are also noted (Crow et ai, 1981, Rhodora 

 82: 259-299). 



We invite comments and/or criticisms on this treatment. Infor- 

 mation on any species omitted or any known localities not documented 

 by us will be welcomed. If anyone is interested in specific localities of 

 any of the species indicated on the dot maps, please contact us. 



Dr. C. B. Hellquist, Department of Biology, North Adams State College, North 

 Adams, MA 01247. 



Dr. G. E. Crow, Department of Botany and Plant Pathology, Nesmith Hall, 

 University of New Hampshire, Durham, NH 03824. 



