204 • IOWA ACADEMY OF SCIENCES. 



EQUISETACE^. 



Equisetum L. Horse-tail, Scouring: Rush. 



6. E. arrense L. Very common in low ground. 



7. E. finviatilis L. {E. limosum L.) common in 



marshes; frequently much branched, especially 

 the sterile stems. 



8. E. hijemide L. Rare on dry banks. 



9. E. laer'ujatum, A. Braun. Frequent on dry prairies. 



SPERMATOPHYTA. 



PINACE^. 

 JUNIPERUS L. 



10. ./. virginiana L. Red Cedar. High banks of lakes; 



becoming rare; our only native evergreen. 



typhace^e. 

 Typha L. 



11. T. latifoJia L. Cat-tail Rush. Common through- 



out in marshes. 

 Sparganium L. 



12. S. eiinjcarpmn Engelm Bur-reed. Frequent in 



marshes and along shores of ponds. 



13. S. simplex Hnds. Rare in marshes near Armstrong. 



NAIADACE^. 



PoTAMOGETON L. Poud-wced. 



14. P. natans L. West fork of the Des Moines river at 



Estherville. Also Spirit Lake, Dickenson county. 



15. P. am/plifoUus Tuck. West Fork of Des Moines. 



16. P. lonchltes Tuck. Common, streams and lakes. 



17. P. heterophyllus Schreb. Common in marshes 



throughout; a beautiful species. 



18. P. iHinoense Morong. Lake east of Armstrong, the 



station destroyed by the drying up of the lake. 

 Part of the type material was from this locality. 



19. P. pnrlongus Wu\f. Rare; Iowa Lake. 



