PLANTS OF IOWA 127 



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

 Not frequent. 



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

 In ponds and streams. 



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



Leaved Pondweed. 

 Not frequent. 

 ZANNICHELLIA, L. 



1574. Z. palustris, L. Zennichellia. 

 Frequent. 



NAIAS, L. 



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

 Not frequent. 



SCHEUCHZEEIACE.E. ARROW-GRASS FAMILY. 



TRIGLOCHIN, L. 



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

 Rare. 



SCHENCHZERIA, L. 



1577. 8. palustris, L. 

 Rare. 



ALISMACE-S. WATER-PLANTAIN FAMILY. 



ALISMA, L. 



1578. A. plant ago-aquatica, 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. 



SAGITTAEIA, L. 



1581. 8. rigidij Pursh. Sessile-Fruited Arrowhead. 

 Not common. 



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



Arrowhead. 



