WEEDS 341 
10. In the following table the names in each line at the left of the 
vertical line are those of cultivated plants; the names at the right, 
those of wild plants of the same family or even more closely related. 
Explain in each case, as well as you can, why the cultivated plant would 
be unable to maintain itself in competition with its wild relatives if 
they were growing side by side. 
wheat, corn | grasses occurring as weeds 
beets, spinach | pigweeds 
peonies | buttercups 
garden strawberries | cinquefoils 
pansies | blue dooryard violets 
scarlet salvia | catnip 
potato, tomato | Jimson weed, horse nettle, ground cherry 
lettuce | dandelion 
11. How should we treat a lawn infested with dandelions? with chick- 
weed? with undesirable grasses? 
1 Viola papilionacea, V. sororia. 
