WEEDS OF MONTANA. 



35 



36. CLEOME INTEGRIFOLIA, Torr & Gray. 



Indian Pink; Stinkweed. 



A native annual about two feet high with 3-foliate leaves and 

 pink flowers, often troublesome in sandy soil. Frequent in grain 

 fields and waste places east of the Divide and now spreading 

 westward along the railways, where it threatens to become 

 a bad weed. 



37. CNICUSARVENSIS.Hoffm 



Canada 1 histle. 



A perennial European spec- 

 ies with long creeping root- 

 stocks most difficult to extir- 

 pate. Very similar to our na- 

 tive thistles, but the heads are 

 much smaller and the plants 

 tend to grow in clumps or 

 patches, never scattered. In- 

 frequent as yet in the state 

 but becoming established 

 along railroads and in waste 

 places. Occurs at Helena. 

 Bozeman, Libby, Craig and 

 Demersville. Can be eradi- 

 cated only by persistent dig- 

 ging, by smothering with 

 straw, manure heaps, &c, or 

 by choking out with a rank 

 growth of clover. Attack on 

 first appearance and do not 

 permit it to become establish- 

 ed. One of the three plants out- 

 lawed in this state. [Fig. 7.] 



a. Cnicus arvensis, Hoffra. Plant 

 one-tilth. 



