86 



WEED FLORA OF IOWA 



Fig. 4 8- 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 Ejmartweed is la native, glabrous, erect annual, 

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

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

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

 aehene 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. 



