GRASSES OF IOWA. 



885 



of the state, but it must not be assumed that temperature and moisture are 

 the only features that govern the distribution ol these plants. Coming to 

 the eastern part of the state, along the Mississippi, we find such strikinglj 

 southern species as Trioda cupraea, 1 . purpurea, and Tripsacum dacty- 

 loideSj the latter species occurring in Decatur and Wayne counties; Pani- 

 cum filiforme, Aristida intermedia and Eragrostis i>itli<>,Ls. i hrough the 

 northern portion of the state, especially the area affected by the glacial 

 drift, there are a number of typical boreal types such as Hierochloe bore- 



Fig. 261. Morainal lake. Cerro Gordo county, Iowa. Hierochloe borealis, Calamagrostis 

 confinis, Br omus KaJmii and Cypripedium. (Charlotte M. King. Photo. ) 



alts, Br omus kalmii, Calamagrostis confinis, Poa nemoralis and Scolo- 

 chloa festucacea. 



Mr. Sage and Doctor Chappel of the Weather and Crop Service 

 report the temperature data for various stations in Iowa as follows: 



25 



