TRIANDRIA. TRIGYNIA, —6Ot 
128. PROSERPINICA. L. 
Calix superior, 3-parted, persistent. Corolla 
0. Nut triquetrous, 3-celled. 
Subaquatic; leaves alternate, under water pif tifid, 
above Seoucteta: serrate; flowers axillary, Sede _ 
Species. 1. P. palustris. 2. pectinata, Probably only 
a variety of the preceding. 
A genus peculiar to the United States. 
