STHUCTUEB OF THE FORMATION 81 



prairie made by the pouched gopher. After some time the 

 encroaching facies again claim the ground. 



ELEMENTS OF THE LATE ESTIVAL FLORAL ASPECT 



Fades 

 Bouteloua curtipendula. 



Principal Species 



Euphorbia corollata, Kuhnistera purpurea. 



Kuhnistera Candida. Meibomia illinoensis. 



Becondary Species 



Amaranthus torreyi. Mentha canadensis. 



Asclepias incarnata. Meibomia canadensis. 



A. verticiliata. Polygonum pennsylvanicum. 



Astragalus carolinianus. Panicum capillare. 



Cassia chamaecrista. Katibida pinnata. 



Cicuta maculata. Silphium laciniatum. 



Convolvulus sepium. S. integrifolium. 



Elymus canadensis. S. perfoliatum. 



Heliopsis scabra. Solidago rupestris. 



Hieracium longipilum. Scutellaria lateriflora. 



Laciniaria squarrosa. Teucrium canadense. 



Lactuca canadensis. T. occidentale. 



L. ludoviciana. Verbena hastata. 



Lespedeza capitata. V. stricta. 



Linum sulcatum. Vernonia fasciculata. 



Lycopus americanus. V. gigantea. 



Lythrum alatum. 



The late estival floral aspect is set off here in order to 

 note more accurately the gradual changes in the floral cov- 

 ering. It is not considered an aspect complete in itself but 

 rather a division of one. Like the late vernal aspect, it is 

 a period of transition. Bouteloua curtipendula is the only 

 new facies, and its distribution has already been noted. 

 Kuhnistera purpurea, K. Candida, and Meibomia illinoensis. 



6 



