NOTES ON THE AQUATIC PIIENOGAMS OF IOWA. 137 



Vol. V. (1891). Much help has also been derived from Prof. 

 Maciiiillan's Mcias^crmce. of the Minnesota Valley (1892). 

 Dr. Morong's Naiadaccce of North America and J. G. Smith's 

 Revision of the JVorih American Species of Sony-it tar ia and 

 Lophotocarpiis have been followed in those groups. In the 

 remaining portions the treatment, with a few exceptions, is 

 essentially that of Grafs Afanital, 6th edition. 



Thanks are due Dr. J. C. Arthm", of Purdue University, 

 Lafayette, Indiana, Mr. E. W. D. Holway, of Decorah, Iowa, 

 Prof. A. S. Hitchcock, of the Kansas Agricultural College, 

 Edmund P. Sheldon, of the University of Minnesota, and 

 Prof. B. Shimek, of the Iowa State University, for valuable 

 assistance. Mr. F. Reppert, of Muscatine, Iowa, has greatly 

 aided me bv the loan of specimens, literature, and by furnish- 

 ing manv valuable notes. Prof. W. A. Kellerman, of the 

 Ohio State Universit}-, kindly looked over for me a portion 

 of Dr. Arthur's collection now in the herbarium of the late 

 Dr. Townshend. Prof. L. H. Pammel, of the Iowa Agricul- 

 tural College, kindly loaned me for study the collection of 

 Iowa aquatics in the herbarium of that institution. Finally, I 

 desire to thank Prof. T. H. Macbride, of the Iowa State Uni- 

 versity, for his kindness and the efficient aid he has rendered 

 me in man}- ways. 



ARACEiE. 



A R IS. EM A Mart. Flora, II., 459 (1831). 



I. K. TRiPiiYLLUM [Linii.) Torr. Fl. N. Y., II., (1843). 



Wats, and Coult., Gray's Man., 6th ed., 549; Arthur, Fl. 

 Iowa, 30; Hitchcock, Ames Fl , 521 ; Macmillan, Metas. Minn. 

 Val., 132. 



Common throughout: preferring low% rich ground in woods. 

 Flowering in May or June, the fruit maturing late in August. 



Decorah, Hohvay ; Iowa City, JMachridc ; Ames and Charles 

 City, Arthur: Emmet count}-, Cratty ; Le Claire, RoIJs; 

 Muscatine, Reppert : Winnebago county, Shimei^. 



A 2 



