NUMBER AND KINDS OF WEEDS ON DIFFERENT SOILS 663 



Fig. 517. A cornfield from which Quack Grass was removed by hoeing and 

 cultivation. In adjacent check it formed a sod. The check was given the 

 ordinary methods of cultivation. 



(Photographed by Colburn.) 



* Convolvulus arvensis (Euro- 



pean bindweed) 



* Polygonum convolvulus (Black 



bindweed) 



* Polygonum aviculare (Knot- 



grass) 



*Rumex sp. (Dock) 



*Tussilago farfara (Coltsfoot) 



* Mentha arvensis (Pepper- 

 mint) 



*8inapis arvensis (Common 

 mustard) 



*Sonchus arvensis (Field sow 

 thistle) 



*Stellaria media (Chickweed) 

 Papaver sp. (Poppy) 

 ^Ranunculus arvensis (Corn 

 crowfoot) 



* Viola sp. (Violet) 

 Potentilla anserina (Silver 



weed) 



Aethusa cynapium (Fool's 

 parsley) 



Scandix pecten-veneris (Ven- 

 us' comb) 



Senecio vulgaris (Groundsel) 



* Galium aparine (Cleavers) 

 Vicia saliva (Vetch) 



