DESCRIPTIVE MANUAL 



25 



Fig. 12. Foxtail and other weeds in back dooryard. Too many sucli places 



in Iowa. 

 (Photographed by Charlotte M. King.) 



Sandbur (Cenchrus tribuloides L.). 



Description. — Annual, with spreading or ascending, much- 

 branched culms, rarely 1 ft. high, somewhat compressed ; leaves flat 

 or simply folded, about 6 in. long, acute, finely serrulate along the 

 margins; sheaths generally much exceeding the intemodes, hairy 

 along the margins and at the throat; burs containing the spike- 

 lets, 6-20, nearly globose, covered with strong and more or less 

 pubescent, barbed spines, which become very hard at maturity and 

 readily fall off. 



Distribution. — Common in eastern North America, sandy 

 shores of lakes, streams, and sandy soil. In Iowa, common on 

 Muscatine Island, railroad embankments, gravel knolls, and in 

 Polk, Clinton, Muscatine, Scott, Woodbury, Linn, Jackson, John- 

 son, Dubuque, Webster and Black Hawk counties. 



ExtermiTMtion. — This weed is easily exterminated by cultivation. 

 The roots are fibrous and exposure to the sun for a short time will 

 destroy the weed. 



