AMBROSIACE^. Ragweed Family. 



Iva axillaris, Pursh. Small-flowered Marsh Elder. 



In dry alkaline soils from the Missouri valley west- 

 ward. 



Iva xanthiifolia, (Tresen.) Nutt. Burweed. Marsh Elder. 

 In waste places from the Missouri valley eastward and 

 in the Black Hills. 

 Ambrosia triflda, L. Great Ragweed. Bitterweed. 



In thickets and waste places from the Missouri valley 

 eastward. 



Ambrosia trifida integrifolia, (Muhl.) T. & G. 

 With the type, common. 



Ambrosia artemisiaefolia, L. Ragweed. 



Abundant in waste places along roads and in culti- 

 vated field from the Missouri valley eastward, rare in 

 the Black Hills. 



Ambrosia psilostachya, DC. Western Ragweed, 



In light soils throughout the state; more common trom 

 the Missouri valley westward. 



Gaertneria discolor, (Nutt.) Kuntze. White-leaved 

 Gaertneria. 

 Franseria discolor, Nutt. 



In dry soils in the Black Hills and the adjoining plains. 



Xanthium Caiiadeiise, Mill. American Cocklebur. 



On loose, sandy soils bordering streams and lakes 

 from the Missouri valley eastward. 



COMPOSITE. Thistle Family. 



Vernonia fasciculata, Michx. Western Iron Weed. 



Common in low places from the Missouri valley east- 

 ward. 



Eupatorium maculatum, L. Spotted Joe-Pye Weed. 



In swampy ground in the Minnesota and Sioux valleys 

 and the Black Hills. 



