jaa NATURAL HISTORY BULLETIN. 



Ponds and margins of lakes. This species has the floating 

 leaves more crowded and of a stockier growth than P. lon- 

 chites with which it is often confounded. "The plant confines 

 itself mostly to rather shallow water on the margin of sloughs 

 and ponds. The plants are often left exposed in the mud, in 

 which, if it does not become too dry, the roots survive and 

 produce short shoots bearing 3 to 4 leaves." — Rcppert. 



Emmet county, rare, C ratty ; Ames, infrequent, Hitchcock; 

 Muscatine, the most common of the large-leaved species, 

 Rcppert. 



7. P. pr/Elongus Wulfen. Roem. Arch., III., 331 (1803-5). 



Morong, Naiad. N. A., 32; Wats, and Coult., Gray's Man., 

 6th ed., 562; Upl am, Fl. Minn., 136; Arthur, Fl. Iowa, 30; 

 Beal and Wheeler, Fl. Mich., 146. 



Deep water, lakes and ponds. July, August. 



Clear Lake, Arthur ; Okoboji and Spirit Lakes, Hitchcock: 

 Iowa Lake, C ratty. 



Note. — P. lucens Linn. Spec. PI., 126 (1753). Specimens without flow- 

 ers or fruit of what appears to be this species were collected by Professor 

 Hitchcock near Ames and are in the herbarium of the Agricultural College. 



8. P. perfoliatus Linn., var. rich ardsoinii A. Bennett. 

 Jour. Bot., XXVII., 25 (1889). P. lanceolatus Sm. Eng. 

 Bot., 1985 (1808). P. perfoliatus var. lanceolatus Rob- 

 bins in Gray's Man., 5th ed., 488 (1867). 



Morong, Naiad. N. A., 33; Wats, and Coult., Gray's Man., 

 6th ed., 562; Arthur, Cont. Fl. Iowa, V.; Upham, Fl. Minn., 

 137. 



Shallow water in lakes, ponds, and streams — a most beau- 

 tiful plant. July. I have not seen the typical P. fcrfoliatas 

 from Iowa. 



Okoboji and Spirit Lakes, Hitchcock; Emmet county. 

 C ratty. 



9. P. zoster^efolius Schuiu. Enum. PI. Sael, I., 50 (1801), 



P. compressus Pries. Nov. ed. 2. 44 (1828). non Linn. 



