STATE HORTICULTURAL SOCIETY. 479 



Not common. In this region only a few localities are known; 

 in La Crosse, which is now obliterated, and in several other 

 places a few straggling specimens. In eastern United State this 

 weed is especially troublesome, but in Wisconsin and Minnesota 

 it is rare and somewhat local. 



Tanacetum vulgare, L. Common Tansy. 



At one time largely cultivated as a garden plant, and now 

 thoroughly naturalized. Along borders of fences and roadsides. 

 This perennial is somewhat difficult to exterminate. 



Artemisia biennis, Willd. Biennial Wormwood. 



Common in waste j)laces, dooryards and roadsides. Eapidly 

 spreading eastward. 



Arctium lappa, L. Burdock. 



Along fences, in waste places in rich soil. The plant persists 

 where once established, but does not spread as rapidly as many 

 of our other weeds, as most farmers cut the plant off, not allow- 

 ing it to mature its fruit. 



Gnicus arv>e7isis, Hoffm. Canada Thistle. 



Fortunately this plant is not as common here as it is in the 

 eastern states. Mr. J. S. Harris reports it from Trempeleau 

 Co., Wis., and in Upham's catalogue of The Flora of Minnesota, 

 it is reported from Fillmore Co. In July, 1886, I found it in 

 the southern part of La Crosse Co., Wis., where it is said to have 

 established itself some fifteen to twenty years ago. Prof. Beal 

 says: "Its course westward is likely to be checked by the 

 fact that it has usually failed to produce seeds on the prairies." 

 But it spreads freely below ground. It is a common weed of 

 fields in Europe. Linnaeus in his Flora Lapponica, considered 

 it one of the greatest pests of the fields. (George Thurber, 3.) 



Thaer recommends deep plowing, several times in a season, and 

 and after each plowing, to pull up the root stocks. Also that a 

 good field of Lucerne Medicago or Onobrychis Sativa, will destroy 

 it. Prof. Beal, (1) finds Eed Clover a good weed exterminator. 



Canada Thistle seems to be most abundant on loamy soil. 



Gnicus Lanceolatus Hoffm. Common Thistle. 



This is likewise a common weedy plant of Europe, and in this 

 region very troublesome, at times especially, in loose and rich 

 soil. It is a biennial and hence is much easier to deal with. 



Cnicus pumilum, Spring, Pasture Thistles. 



Sometimes troublesome in dry rocky pastures. 



Cichorium intybus, L. Succory or Cichory. 



Has become established along roadsides, and proves a [most 

 pesistent weed where introduced. 



