380 



GRASSES OF IOWA. 



detail all of the' regions of the state but to call attention to a few of the 

 leading physiographic features and the plants found there. The subject 

 has been discussed brief!)' by the writer in several papers. 



Fig. 258. Forest, Allamakee county, Iowa. Tazus Canadensis, Poa Wolfii, Bet- 

 ulapapyrtfera, Abies balsamea and Dlerrilla triflda (L. H. Pammel, Photo.) 



Topographic features exert a marked influence on the distribution 

 of plants, such differences are readily observed in the distribution of 

 grasses, even in a state with a topography so uniform as in Iowa. It will, 

 therefore, be of interest to discuss some of these features. The greater 

 part of Iowa lies betwen 90 and 96 longitude, being nearly 90 at 32 

 latitude just north of Clinton and 96 30' at the west side, in Plymouth 

 county. The boundary line on the south is somewhat more than 40° 

 30', on the north it is 43 ° 30'. The southeastern county, Lee, exceeds 



Some Ecological note9 on Iowa Grasses. Proc. Soc. Prom. Agr. Sci. 1898: 204. 

 Contr. Bot. Dept. I. 8. C. 12. 



Preliminary notes on the Flora of Western Iowa, especially from the Physiographical, 

 Ecological Standpoint. Proc. la. Acad. Sci. 9: 152. Contr. Bot. Dept. I. S. C. 21. 



