PLANTS OF IOWA 127 



1571. P. pectinatus, L. Fennel Leaved Pondweed. 

 Not frequent. 



1572. P. nuttallii, Cham. & Sch. Nuttall's Pondweed. 

 In ponds and streams. 



1573. P. spathulceformis, (Bobbins) Morong. Spatulate- 



Leaved Pondweed. 

 Not frequent. 

 Zannichellia, L. 



1574. Z. palustris, L. Zennichellia. 

 Frequent. 



Naias, L. 



1575. N. flexilis, (Willd.) Bost. & Schmidt. Slender Naias. 

 Not frequent. 



SCHEUCKZERIACE.E. ARROW-GRASS FAMILY. 



Triglochin, L. 



1576. T. maritima, L. Seaside Arrow Grass. 

 Rare. 



SCHENCHZERIA, L. 



1577. 8. palustris, L. 

 Rare. 



ALISMACE-E. WATER-PLANTAIN FAMILY. 

 Alisma, L. 



1578. A. plant ago-aquatic a, L. Water-Plantain. 

 Common in shallow water or mud. 



1579. A. tennellum, Mart. Dwarf Yater-Plantain. 

 In mud. 



Echinodorus, Rich. 



1580. E. cordifolius, (L.) Griseb. Upright Bur-Head. 

 Infrequent. 



Sagittaria, L. 



1581. 8. rigidi, Pursh. Sessile-Fruited Arrowhead. 

 Not common. 



1582. 8. longirostra, (Micheli) J. G. Smith. Long-Beaked 

 Arrowhead. 



