KINGIIEA D—RA G WEED 65 



Kinghead (Ambrosia trifida L.) 



Other common names. — Tall or giant ragweed, house cane, greater 

 ragweed, crown weed, bitter weed, tall ambrosia, richweed. king- 

 weed. 



Description. — Kinghead is an annual weed which grows from 

 three to fifteen feet high. It grows so rank that it often crowds out 

 all other vegetation. The leaves and stem are very rough. The 

 lower leaves are deeply cut, while those near the top are entire. The 

 whole plant is pale green. The upper flowers produce the pollen 

 or yellow dust. This pollen falls on the lower flowers which develop 

 the seeds ; the latter flowers are found near the base of the leaf where 

 it joins the stem. The seed is about one-fourth of an inch long, 

 tapering to the base. At the top, or large end, of the seed there are 

 from six to eight points. The plant flowers in July and ripens its 

 seeds in August. It is found along roadsides and by lakes and run- 

 ning streams throughout the State, but especially in the northwestern 

 part. The seed is found in cereal grains, especially in wheat, from 

 which it is hard to separate with the ordinary cleaning machinery. 



Eradication. — Cease sowing grain containing the seeds. Because 

 of the great difficulty of separating from seed grain it is desirable to 

 buy seed from an uninfested farm or locality. When necessary to 

 use seed wheat containing seeds of kinghead, much of the latter may 

 be floated off by immersing the seed grain in water. The kinghead 

 is light and may be skimmed off when it rises to the top. The weeds 

 usually appear near the roadside or edges of the fields, where they can 

 be cut with a mower before the seed matures. In some seasons 

 they will spread through the grain crops and crowd them badly. 

 Then they should be hand pulled or cut with a scythe. The main 

 point is to prevent them from going to seed. These weed seeds in 

 wheat seriously injure its flour-making quality and lessen the value 

 of the crop. 



Ragweed (Ambrosia artemisiaejolia L.) 



Other common names. — Smaller ragweed, hogweed, bitter weed, 

 carrot weed, Roman wormwood. 



Description. — Ragweed is somewhat similar to kinghead. It 

 differs in that both plant and £eed are smaller, and its leaves are 

 more deeply cut. It is an annual weed which grows from one to three 

 feet high. The stem, branches, and leaves are much divided and 

 somewhat hairy. As in kinghead the upper flowers pollinate and 

 fertilize the lower ones. When the plant is discharging its pollen, 

 it has a very yellowish appearance. This occurs late in July and 



