GRASSES OF IOWA. 



393 



death of the older and inner parts of the bunch. The border contains 

 living plants, the rootstocks with the adjacent soil are naturally raised. 

 < )f the striking bunch grasses belonging to this series we may mention 

 Calamovilfa longifolia and Sporobolus heterolepis. 



HALOPHYTIC. 



A close studs of the structure of halophytes indicates that these 

 plants are really xerophytic in their nature. Halophytic plants, "1 

 course, are such as are adapted to salt marshes and alkaline places, and in 

 respect to their need of water and protection, they behave like the xero- 

 phytic plants. Only a single species occurs in the state of Iowa that orig- 

 inal lv was a strongly alkaline or salt marsh plant, namely the squirrel tail 

 grass. This species no longer confines itself to these alkaline marshes but 

 is found everywhere. 



Fig 265. Poa pratensis, Blue Grass in a planted grove. The conditions here are similar t those 

 occurring in pastured woodlands. (Charlotte M. King, Phoio). 



MESOPHYTIC. 



The mesophytic type grades between xerophytic on the one hand and 

 hydrophytic on the other. They are not able to stand the drying influ- 

 ences of a sandy soil so well as halophytic plants, but are adapted to our 



