15. 



kinds may be a means of scattering weed seeds. Small weed 

 seeds may cling to mud of wheels and be carried to some distance 

 away from where the seed was produced. 



Threshing Machines. Many farmers in northern Iowa where 

 quack grass is becoming abundant claim that the seed of this 

 weed, mustard, vetch, etc., is scattered by means of the threshing 

 machine. I have in some instances verified this claim. 



Cultivation. The "roots" of various weeds are easily scat- 

 tered by the cultivator. A small patch of quack grass in the 

 corn field may be the means of widely scattering the plant over 

 the field. 



Packing material. Various kinds of packing material such as 

 is used for packing crockery has been the source of the intro- 

 duction of Canada thistle, Awned Brome grass, etc. I have traced 

 the origin of these weeds in this way. 



Wool. The seeds of many weeds cling to the fleece of sheep 

 and where the wool is cleaned, and the debris thrown away these 

 weeds spring up. Common teasel which is used to card wool is 

 usually found around the woolen mill. Burdock, cocklebur, sand 

 bur, and hound's tongue are commonly scattered in this way. 



PLANTS CULTIVATED FOR ORNAMENTAL PURPOSES. 



In this state we have two conspicuous examples of weeds which 

 at one time were commonly cultivated for ornamental purposes 

 which have become troublesome weeds, namely, the toad flax and 

 bouncing betty. Here and there the European bindweed has 

 been scattered in this way. These have become troublesome weeds, 

 difficult to exterminate because of their perennial character. Live 

 forever, cypress spurge, purple pigweed and Mexican firweed are 

 other illustrations of weeds introduced in this way. 



Plants Cultiva-ted for Food. We have only a few weeds that 

 belong to this class in Iowa, but in some parts of the United 

 States they are more numerous. The conspicuous examples are 

 chicory, wild carrot, vegetable oyster plant, hemp and parsnip. 



THE WEEDS OF THE IOWA WEED LAW. 



The Thirty-third General Assembly passed a law making it 

 the duty to remove certain weeds from the public highway, 

 lands adjacent thereto, streets of cities and villages, right of 

 way of railroads and public lands. 



Destruction of Weeds. 

 Thirty-third General Assembly of the State of Iowa. 



Section 1. Land Owners or Tenants to Destroy Weeds 

 When. It shall be the duty of every person, firm or corpora- 

 tion owning, occupying or controlling lands, town and city lots, 

 land used as right of way, depot grounds or for other purposes 

 to cut, burn or otherwise entirely destroy all weeds of the kinds 



