152 FARM WEEDS OF CANADA 



COMMON RAGWEED (Ambrosia artemisiifolia L.) 



Other English names: Roman Wormwood, Smaller Ragweed, 

 Hog weed. 



Native. Annual. A coarse, branching plant with hairy 

 stems, 2 to 4 feet high. Leaves thin, smooth above, grayish 

 white beneath from short, downy hairs, much cut up, pinnatifid, 

 twice divided. Flowers closely resemble those of Great 

 Ragweed but are smaller. * Occasional plants bear only 

 female flowers. 



The seed (Plate 75, fig. 79) is from 1/12 to 1/6 of an inch 

 long, dull, light straw to dark brown, somewhat pear-shaped, 

 the apex long and tapering to a sharp point. The surface is 

 veined and slightly ridged lengthwise. This ridge usually termin- 

 ates in sharp teeth, which form a circle around and point toward 

 the apex. These teeth vary in number, size and regularity and 

 are sometimes entirely absent. The outer covering of the seed 

 is brittle and may be more or less broken away, thus revealing 

 a smooth, brown, inner cover. The breaking off of this second 

 coat shows the inside seed, which is greenish- white, nearly round 

 and slightly pointed at the base. Ragweed seed appears in red 

 clover under these different forms, sometimes in large quantities, 

 and can be separated only with much difficulty. 



Time of flowering: July; seed ripe in August. 



Propagation : By seeds, carried in the seeds of grain, clovers 

 and grasses. 



Occurrence: In rich land and w^aste places throughout 

 eastern Canada and in the Prairie Provinces. Exceedingly 

 prevalent in southwestern Ontario. 



Injury: This weed has a detestable odour and flavour and 

 is disliked by cattle in pasture or hay; its presence results in 

 considerable waste of fodder or forage. Where it is abundant 

 it will taint milk. It is a vigorous plant, occupies much space, 

 and thus reduces the crop yield. 



Remedy: Sow clean red clover seed. Stubble lands where 

 this weed is prevalent should be shallow-plowed directly after 



