204 
IOWA ACADEMY OF SCIENCES. 
EQUISETACE^E. 
Equisetum L. Horse-tail, Scouring Rush. 
6. E. arvense L. Very common in low ground. 
7. E. fluviatilis L. (E. limosum L.) common in 
marshes; frequently much branched, especially 
the sterile stems. 
8. E. hyemale L. Rare on dry banks. 
9. E. laevigatum , A. Braun. Frequent on dry prairies. 
SPERMATOPHYTA. 
PINACE^:. 
JUNIPERUS L. 
10. J. virginiana L. Red Cedar. High banks of lakes; 
•becoming rare; our only native evergreen. 
TYPHACE^E. 
Typha L. 
11. T. lati folia L. Cat-tail Rush. Common through- 
out in marshes. 
Sparganium L. 
12. S. eurycarpum Engelm Bur-reed. Frequent in 
marshes and along shores of ponds. 
18. S. simplex Huds. Rare in marshes near Armstrong. 
NAIADACEAS. 
Potamogeton L. Pond-weed. 
14. P. natans L. West fork of the Des Moines river at 
Estherville. Also Spirit Lake, Dickenson county. 
15. P. amplifolius Tuck. West Fork of Des Moines. 
16. P. lonchites Tuck. Common, streams and lakes. 
17. P. heterophyllus Schreb. Common in marshes 
throughout; a beautiful species. 
18. P. illinoense 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. prcelongus Wulf. Rare; Iowa Lake. 
