THE PRAIKIES 



183 



In addition to the species included in the table there are 

 several which belong to dry prairies, but they are local and quite 

 rare, and were not collected at the localities specifically included 

 in the table. They are given in the following supplementary list : 



Agropsrron tenerum Vasey. 



Amorpha microphylla Pursh. 



Artemisia canadensis Miehx. 



Aster amethystinus Xutt. 



Aster ericoides L. 



Bouteloua oligostachya ( Xutt.) Torr. 



Cirsium Hillii i Canby) Feru. 



Euphorbia dictyosperma F. & M. 



Gaura parviflora Dougl. 



Oxybaphus floribundus Chois. 



Oxybaphus linearis ^ Pursh) Rob. 



Sphenopholis obtusata var. lobata (Trin.) Sorib. 



Ssmthyris Bullii (Eaton) Haller. 



Tradescantia brevicaulis Raf. 



These species are found in the driest parts of the state, with 

 the exception of the last two but one chiefly in the western part of 

 the state and they are frequently associated with those included 

 in the special list of the species belonging more distinctly to the 

 dry plains which have invaded the prairie. 



A second supplementary list contains species which frequently 

 occur on the prairie, but usually near the border of groves or in 

 somewhat sheltered localities. They are sometimes associated 

 with the invaders from the groves and bogs. The list follows : 



Agastache scrophulariaefolia (Willd.) Ktze. 

 Amphicarpa Pitcheri T. & G. 

 Clematis virginiana L. 

 Coreopsis tripteris L. 

 Lobelia leptostachys A. DC. 



In preparing the foregoing table and accompanying lists the 

 writer studied the flora of about sixty localities, chiefly in Iowa, 

 and the studies have extended over a period of twenty years. 



As only twelve of these localities are represented in the table 

 of plants, and as only those species are included of which speci- 

 mens were collected and deposited in the herbarium of the State 

 University of Iowa, a number of blanks appear in the table. 



