126 



WEED FLORA OF IOWA 



Fig. 71-A. Distribution of Corn Cockle. 



long peduncled; calyx lobes long, linear, surpassing the purplish 

 red petals ; seeds large, roughened and black. 



Distribution. — A weed long known as troublesome in European 

 grain fields, and widely scattered throughout the grain growing sec- 

 tion of North America. It is most abundant in Iowa in the wheat- 

 growing section but occasionally is found in other places around 

 grain elevators. 



ExtermiTiation.- — This weed is an annual and in order that it may 

 be checked in its spread, use only clean seed. The seed should be 

 put in clean soil. 



Fletcher and Clark recommend as follows : "In the prairie pro- 

 vinces, harrowing the grain crop just before it emerges from the 

 gound and again when it is about three inches high keeps down this 

 weed. Where the land is infested with purple cockle, a thorough 

 summer fallow is the best method of getting rid of it. ' ' 



White Campion {Lychnis alba Mill.). 



Description. — A freely branching biennial, with a slightly plea- 

 sant odor; leaves ovate-oblong or ovate-lanceolate; flowers loosely 

 paniculate, white or pink, fragrant; capsule ovoid-conical, swelling 

 with the ripening of the pod ; petals 2-clef t, crowned. 



Distribution. — Introduced with clover seed from Europe, not, 

 however, as common in the east as Lychnis dioica. 



