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WEED FLORA OP IOWA 



Fig. 48-A. Distribution of Bushy Knotweed. 



Distribution. — From Manitoba to Texas, also in Pennsylvania; 

 frequent in fields in many parts of Iowa, in Story, Boone, Worth, 

 and Cerro Gordo counties. 



Extermination. — Easily exterminated by cultivation. 



Pink Smartweed {Polygonum lapathi folium L.). 



Description. — Pink smartweed is a native, glabrous, erect annual, 

 with stem swollen at the nodes; lanceolate, acuminate leaves with 

 short ciliate petioles; racemes panicled, nodding, with many flow- 

 ers ; calyx white or pink, small 5-parted ; 6 stamens, style included ; 

 achene lenticular. 



Distribution. — This weed occurs from New England to Nebraska 

 and Louisiana. Native to Europe, and common in eastern North 

 America ; everywhere in Iowa, particularly in moist situations. 



Extermination. — Easily exterminated, after drainage of slough, 

 by cultivation. 



