out west of the Laboratory, the somewhat higher knob northwest 

 of it, the ridge north of j\Iiller 's Bay, and a gravelly knob at the 

 head of West Okoboji lake. 



II — Similar grayelly knobs east of the head of West Okoboji 

 lake, and east and northeast of the Inn. These two groups typify 

 the flora of all the gravelly ridges of the region, such as Twin 

 Mounds, the ridge southeast of Terrace Park, and the knobs in 

 the Spirit lake region. 



III — The general rolling upland prairie west of West Oko- 

 boji lake, somewhat less xerophytic than I, with a fine drift soil 

 of somewhat variable quality. 



IV — The general prairie between East and West Okoboji 

 lakes. This is also mostly somewhat elevated and rolling, and 

 includes the region between the head of West Okoboji lake and 

 Spirit lake. The groups III and IV include the general prairie 

 flora of the entire region. 



V — The sandy prairie at Terrace Park and west of Emer- 

 son 's Bay, and similar prairie at the north end of West Okoboji 

 lake. This represents older sandy beaches which are not now 

 ordinarily reached by the waves. 



VI — A similar area between East Okoboji and Spirit lakes, 

 and another on the north side of Spirit lake. 



VII — This column includes the prairie species which have 

 been found in the more or less semi-xerophytic borders and open- 

 ings in groves along the west side of West Okoboji lake, where 

 they mingle more or less with forest species. 



VIII — Similar areas along the east side of West Okoboji lake, 

 including the banks south of Pillsbury's Point. 



Collections have been made over the entire area mapped but 

 it would be impossible to give all the details of distribution with- 

 out expanding this paper beyond reasonable limits. It is be- 

 lieved that the presentation of these regional lists will give a 

 sufficient insight into the nature and distribution of the prairie 

 flora of the region. 



1 1 1 II 



III| IV 



V 



VI 



VII 



VIII 





Subkingdom III PTERIDOPHYTA| 

 Family Equisetacece | 

 Equisetmn arvense L. i| 

 Eqiiisetum hyemale robiistum (ABr.) j 

 A. A. Eaton c| 





4 1 4 



1 



1 4 





5 









29 



