'37 



Polygonum emersum, (Mich.) Britton. Swamp Persi- 

 caria. 



In swamps and edges of ponds throughout the state. 



Polyg'oimm lapatliifoliimi, L- Dock-leaved Persicaria. 

 In waste places throughout the state; rare west of the 

 Missouri, except in the Black Hills. 



Polygonum lapathifoliuiii incaimm, (Schmidt.) Kock. 

 Same range as the type. 



Polygoimm Peimsylvaiiicuiii, L. Pennsylvania Persi- 

 caria. 



In moist soil from the Missouri valley eastward. 



Polygoimm Persicaria, L. Ladies' Thumb. 



Common in waste places from the Missouri valley 

 eastward, and in the Black Hills. 



Polyg'oimm hyclropiper, L. Smart- weed. 



In moist places in the Minnesota and Sioux valleys. 



Polygonum pimctatum, Ell. Water Smart-weed. 

 Polygonum acre^ H. B. K. 



In cold swamps in the Minnesota valley. 



Polygonum aviculare, L. Knot-grass. 

 In waste ground throughout the state. 



Polygouum littorale, Link. Shore Knot-weed. 

 In waste places in the Black Hills. 



Polygonum erectum, L. Erect Knot- weed. 

 In dry soils throughout the state. 



Polygoimm ramosissiiimm, Michx. Bushy Knot- weed. 

 A common weed in dry soils, throughout the state. 



Polygoimm cainporum, Meisu. Prairie Knot-weed. 

 On prairies from the Missouri river eastward. 



Polygoimm temie, Michx. Slender Knot- weed. 



In ground that has been broken from the Missouri 

 river eastward. 



