370 IOWA ACADEMY OF SCIIENCE Vol. XXV, 1918 



t'oatiires in tlie conception of the formation are, as described by 

 Warraino-, an expression of certain well defined conditions of 

 life and are not concerned with floristic ditferences. On this 

 basis the Prairie Province under inspection may be divided into 

 the follo\\'ing regions with reference to : 



A — Topography Swamp 



I Upland Ponds 

 Hilltop B — Formations 

 Slope I Upland prairie 

 Meadow II Meadow 



II Lowland III Swamp 

 ]\[eadow IV Pond 



Stipa-Bouteloua Formation. 

 Soil gravelly, sandy loam or loam. 

 Arrangement : copious. 



The main consocies as represented liy more prominent 

 species are : 



A. Consocies — Bouteloua. 



Location : Hilltop, gravelly loam. 



The principal species are: 



Bouteloua curtipendula, Bouteloud JiirsKta, Koeleria cris- 

 tata, Carex pennsylvanica, Astragalus caryocarpus, Comandra 

 umbelkita, Anemone cylindrica, Anemone patens var. ^yolf- 

 gangiana, Agoseris cuspidata, Oenothera serrukita, Solidago 

 speciosa, Liatris cyli'ndriccb, Euphorbia corolkita, Lithosper- 

 muni canescens, Lithospermum a-ngiisti folium, PetaXostemum 

 purpureum, Poly gala verticillata. 



The societies of the seasonal aspects are : 



(1) Spring aspect. 



Anemone patens var. Wolfgangiana, Comandra umhellata, 

 Agoseris cuspidata. 



(2) Summer aspect. 



Bouteloua curtipendula, Bouteloua Itirsuta, Koeleria cris- 

 tata, Polygala verticillata. 



(3) Fall aspect. 



Bouteloua hirsuta, Bouteloua curtipendula, Andropogon fur- 

 catus, Liatris cylindrica, Aster azureus, Solidago speciosa. 



