TRIANDRIA, TRIGYNIA. ^1 



128. PROSERPINICA. X. 



Calix superior, 3-parted, persistent. Corolla 

 0. JSTut triquetrous, 3-celled. 



Subaquatic; leaves alternate, under water plnnatifid 

 above lanceolate, serrate; flowers axillary, sessile. ' 



Species. I. P. palustns. 2. pectinaia. Probably only 

 a variety of the preceding. 



A genus peculiar to the United States. 



