of the conclusion reached by Whitney * and others, that the flora 

 of the prairies is determined by the fineness of the soil. 



The tabulated list of plants which follows presents a compara- 

 tive view of the flora as observed on the several sandy areas. It 

 is not presumed that the lists are complete, but they well show 

 the character of the flora. Perhaps column VI is the least com- 

 plete, as it is very difficult to determine the limits of such areas. 

 It should be stated that the collections on which this report is 

 based are deposited in the Herbarium of the State University 

 of Iowa. 



It will be observed that the several areas, even when of the 

 same type, do not show a uniformity of species. Thus the species 

 common to II and III, the river sands areas, number 74; those 

 found only in II number 70 ; and those found only in III number 

 85. The dune areas IV and V, from opposite sides of the state, 

 have 45 species in common, while 167 are found only in IV and 

 42 only in V. 



The total number of species listed is 397. Of this number 

 186 were found in the areas represented in column I; 148 in 

 column II ; 163 in column III ; 217 in column IV ; 88 in column 

 V ; 54 in column VI ; and 19 in column VII. 



According to habitat aad habit, the species listed may be 

 grouped as follows: 



! I 





III 



IV 



V 



VI 



VII 



Prairie species 



99 



88 



86 



138 



39 



37 



12 



Species of open places, mostly prairie 



7 



9 



8 



13 



5 



6 



2 



Usually in sand, sometimes on prairie 



7 



5 



16 



13 



9 







Dry sand species 



9 



15 



22 



28 



6 



3 



2 



Wet sand or marsh species 



49 



15 



9 



4 



12 





1 



Forest species 



5 



1 



5 



5 



6 



4 





Introduced weeds 



10 



15 



17 



16 



11 



4 



2 



This tabulation emphasizes the fact that the sand floras con- 

 nect with those of the prairie, forest, and swamp, and that the 

 character of the three latter largely determines the character of 

 the first. 



In the plant list, the following symbols are used : 

 The Roman numerals at the head of the columns designate 

 localities as follows : 



*J. D. Whitney. American Naturalist, vol. X, pp. 577-588 and 656-667; 1876. 

 Memoirs of the Museum of Comparative Zoology, vol. VIII, part II, pp. 166-183; 

 1882. 



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