COMPOSITE FAMILY. 



177 



-3 or 4 feet high, usually much branched or bushy. Leaves 2-4 or 5 inches long ; 

 petioles half an inch to an inch and a half long. Staminate heads small, numerous, in ter- 

 minal slender spicate racemes. Pistillate heads solitary or clustered along the lower part 

 of the staminate racemes and bracteate, or in the axils of the upper leaves ; sometimes 

 the heads are dioecious specimens occurring in which the terminal racemes (or rather 

 spikes), as well as the clusters beneath, are all pistillate, and the flowers in small sessile 

 bracteate clusters. 



Cultivated fields and pastures : Canada to Florida. Fl. August -September. Fr. Octo- 

 ber. 



FIG. 118. The Great Ragweed (Ambrosia triflda), upper portion of stem reduced iu 

 size. 



8* 



