i5o 



NATURAL HISTORY BULLETIN. 



Jones county. Cedar Rapids and Iowa City, Macbride; Ames r 

 Arthur; I lamilton county, Rolfs; Muscatine, Refpert ; Mar- 

 shalltown, Stczvirt; Davenport and Waterloo, Hitchcock; 

 Winnebago and Lee counties, Shimek. 



3. S. rigida Pursk. Fl. Am., 397 (1814). 



S. hctcrophylla Pursh. Fl. Am., 396 (1814), not of 

 Schreb. Fl. Fri., II., 119 (1811). 



Smith, Rev. N. A. Sag. and Loph., 23; Wats, and Coult., 

 Gray's Mm.,6thed., 555; Hitchcock, Ames Fl., 520; Arthur, 

 Cont. Fl. Iowa, III. 



Edges of lakes or streams; rather common in the eastern 

 and southern portions of the State. Very variable, especially 

 in regard to size and foliage, July, August. 



Clinton county, Butler; Ames, abundant at Cairo Lake, 

 Hitchcock; Muscatine, in Muscatine slough at the upper 

 bridge, five miles below the city, Reppcrt; Waterloo, Hitchcock; 

 Linn county, Shimek. Specimens collected at Iowa City by 

 Prof. Hitchcock have the submersed foliage closely resembling 

 that of S. teres Wats. 



4. S. GRAMINEA MicllX. Fl. N. A., I., I9O (1803). 



Smith, Rev. N. A. Sag. and Loph., 24; Wats, and Court., 

 Gray's Man., 6th ed., 555; Arthur, Fl. Iowa, 31; Hitchcock, 

 Ames FL, 522; Webb, Fl. Neb., 97. 



Southeast portion of the State; ponds and streams. July. 



Ames and Boone, Bessey; Hamilton count} 7 , Rolfs; Iowa 

 City, M acb ride; Muscatine, Reppcrt; Nevada, Fragier; Carns- 

 forth, Hitchcock, a form approaching S. cristata. 



5. S. cristata Engelm. in Arthur, Cont. Fl. Iowa.V., ( 1882) . 



Proc. Dav. Acad. Sci., IV., 29 (1886). 



S. variabilis var. (?) gracilis^ S. Watson in Gray's Man., 6th 

 ed., 555. in part, not of Engelm. 



Smith, Rev. N. A. Sag. and Loph., 27; Sheldon. Minn. Bot. 

 Studies, Bull. 9. pt. II. 



Monoecious aquatic, rooting in the sand or mud in water a 



