DESCRIPTIVE MANUAL 



99 



Fig. 55-A. Distribution of Black Bindweed. 



The seeds of wild buckwheat do not germinate in the spring until 

 the soil is quite warm. Most of the early plants can be destroyed 

 in the grain crops by an application of the harrow when the grain 

 is about three inches high. The young plants soon root firmly and 

 the harrowing, to be effective, must be done just as they emerge 

 from the ground. ' ' 



CHENOPODIACEAE, GOOSEFOOT FAMILY. 

 This family contains the spinach, sugar beet, beet and salt bushes. 



Winged Pigweed (Cycloloma atriplicifolium (Spreng.) Coult.). 



Description. — An annual with alternate sinuate-toothed petioled 

 leaves ; small inconspicuous flowers in open panicles ; winged seeds ; 

 herb diffusely spreading or often spherical in form similar to the 

 Russian thistle or Iowa tumbleweed. 



Distribution.- — Native from Manitoba, Minnesota, to Illinois, Ark- 

 ansas and the Rocky mountains. In Iowa it is found along Missis- 

 sippi river in Dubuque and Muscatine counties, in Linn county, 

 and along Missouri river. 



Extermination. — This weed is easily exterminated by cultivation. 

 In Iowa has probably been spread with western grass seed and in 

 stock cars. 



