I — The beaches of the Okoboji lakes and Spirit lake. 

 II — Sandy shores and bars of the Iowa river below Iowa City. 



III — Sandy shores and bars of the Cedar and ]\Iississippi rivers 



in Muscatine coimty. 



IV — The dunes of Muscatine county near the Cedar and Mis- 



sissippi rivers. 



V — The dunes of Harrison county west of IVIissouri Valley. 

 VI — The sandy and gravelly ridges along the border of the 



lowan and lUinoian drifts, and elsewhere. 

 VII • — The talus sands at the bases of St. Peter sandstone ledges 

 in northeastern Iowa. 

 The species which are present are indicated in each column by 

 the plus signs. The letters following some of the names have the 

 following significance : 

 a — Species restricted to sands and gravels, 

 u — Species usually found in sand, sometimes on prairies, 

 w — Species of moist grounds or sand, or marsh species, 

 f — Species belonging in the forest, or at least forest borders, 

 i — Introduced weeds. 



0 — Plants of open places and often occurring on prairies. 

 The unmarked species belong to the prairies. 

 In all cases only pure sand or gravel areas without appreciable 

 humus were considered in these studies. 







I 



II 



III 



IV 



V 



VI 



VII 



Subkingdom III PTEEIDOPHYTA 



















Familj 



















Equisetum arvense L. 



0 





+ 



+ 



+ 





+ 





Equisetum hyemale L. 



0 





+ 





+ 



+ 







Equisetum hyemale intermedium Eat. 



0 









+ 









Equisetum hyemale robustum (ABr.) 



















Eat. 



w 



+ 



+ 



1 









Equisetum laevigatum A. Br. 









+ 



+ 



+ 







Subkingdom IV SPEEMATOPHYTA 

















Subclass MONOCOTYLEDONE^ 



















Family Typlmceoe 



















Typha latifolia L. 



w 











+ 







Family Alismacece 













i 





Echinodorus eordifolius (L.) Gr. 



w 











+ j 





Family Gram'mece 



















Andropogon furcatus Muhl. 





+ 







+ 



4- 



+ 





Andropogon scoparius Michx. 





+ 



+ 





+ 



+ 



+ 





Sorghastrum nutans (L.) Nash 









+ 1 + 









Digitaria humifusa Pers. 



i 







1 



4- I 





13 



