Krai, Robert. Xyris (Xyridaceae) of the Continental United States and Canada. Sida 



2 (3): 177-260. 1966. 

 Krai, Robert. Eriocaulaceae of Continental North America north of Mexico. Sida 2 



(4): 285-332. 1966. 

 Lundell, C. L. and Collaborators. Flora of Texas. Vols. I, II, III. Texas Research 



Foundation, Renner, Texas. 1942-1969. 

 MacKenzie, Kenneth Kent. North American Cariceae. N. Y. Bot. Garden. New York. 



1940. 

 Martin, Alexander C, Zim, Herbert S. and Nelson, Arnold L. American Wildlife & 



Plants. McGraw-Hill Book Co., Inc. New York. 1951. 

 Mason, Herbert L. A Flora of the Marshes of California. University of California 



Press. Berkeley. 1957. 

 Matsumura, Y. and Harrington, H. D. The True Aquatic Vascular Plants of Colorado. 



Tech. Bull. Colo. Agri. Exp. Sta. 57. 1955. 

 Mitchell, Richard S. Variation in the Polygonum amphibium complex and its taxonomic 



significance. University of California Publications in Botany. Vol. 45. 1968. 

 Muenscher, W. C. Aquatic Plants of the United States. Comstock Publishing Co., Inc. 



Ithaca. 1944. 

 Munz, Philip A. and Keck, David D. A California Flora. University of California 



Press. Berkeley and Los Angeles. 1959. 

 Niering, William A. The Life of the Marsh. McGraw-Hill Book Co., Inc. New York. 



1966. 

 Pennell, F. W. The Scrophulariaceae of eastern North America. Acad. Nat. Sci. Phila. 



Monogr. 1:1-650. 1935. 

 Rechinger, K. H., Jr. The North American species of Rumex. Field Mus. Nat. Hist. Bot., 



Ser. 17: 1-151. 1937. 

 Reed, Clyde. Selected Weeds of the United States. Agri. Handb. No. 366, Agri. Res. 



Serv., U. S. Dept. of Agri. 1970. 

 Reid, George K. Ecology of Inland Waters and Estuaries. Reinhold Publishing Corp. 



New York. 1961. 

 Sculthorpe, C. D. The Biology of Aquatic Vascular Plants. St. Martin's Press. New 



York. 1967. 

 Shinners, Lloyd H. Spring Flora of the Dallas-Fort Worth Area Texas. Dallas. 1958. 

 Shreve, Forrest and Wiggins, Ira L. Vegetation and Flora of the Sonoran Desert. Stan- 

 ford University Press. 1964. 

 Small, John Kunkel. Manual of the Southeastern Flora. New York. 1933. 

 Standley, Paul C. Trees and Shrubs of Mexico (Contrib. U. S. Nat. Herb. Vol. 23). 



Washington. 1920-1926. 

 Steyermark, Julian A. A Flora of Missouri. The Iowa State University Press, Ames. 



1962. 

 Waterfall, U. T. Keys to the Flora of Oklahoma. Oklahoma State University Press. 



Stillwater. Ed. 3. 1966. 

 Willis, J. C. A Dictionary of the Flowering Plants and Ferns (7th ed. revised by Shaw, 



H. K. Airy). Cambridge University Press. 1966. 

 Wooton, E. O. and Standley, Paul C. Flora of New Mexico (Contrib. U. S. Nat. Herb. 



Vol. 19). Washington. 1915. 

 Young, Gordon. Pollution, Threat to Man's Only Home. Nat. Geograph. Mag. 138(6): 



738-780. 1970. 



1738 



