70 



Fig. 26. 



Ragweed, Hog weed, Bitter weed, or Roman Wormweed. 



Aynhrosia artemisicc folia, (L). 



Eag\veed is an annual. The stem is much branched and slightly 

 hairy, from 1 to 3 feet high. The leaves are very finely divided, the 

 lower surface being of a lighter color than the upper. The flower 

 heads are very numerous, from 1 to 6 inches long, green, and incon- 

 spicious. The flowers are yellow, 1-6 inch across, infertile in the 

 terminal spikes, and fertile only at the base of the spikes. The seed 

 is dark brown, with a sharp tip, around which are arranged 4 to 6 

 spines, 3-16 inches long. They have great vitality and remain in the 

 soil a long time without injury. An average plant produces about 

 5,000 seeds. The seed has a bad taste and gives a peculiar odour to 

 the milk of cows which eat it. 



Time of flowering, July-September. 

 Time of seeding, August-November. 



Dispersal — as an impurity in seed grain ; and by wind and water, 

 being borne long distances by freshets. 



Eradication. For the eradication of this weed, special attention 

 must be given to the fall cultivation of the soil, to prevent seeds from 

 ripening. Gang-plow or cultivate, and harrow stubble ground 

 immediately after harvest, and repeat cultivation at intervals until 

 late in the fall ; then plow or rib up, and follow with a hoed crop. 

 Care should be taken with the hoed crops that no specimens of Rag- 

 weed go to seed. When in grass, go over with a mower in September 

 or October, if any plants are likely to mature seed. Do not sow late 

 maturing crops. Ragweed when eaten by cows causes bitterness in 

 milk. 



