260 NATURAL HISTORY OF THE FARM 
Successful weeds must be able to thrive on the treatment 
accorded to the crop with which they grow. In our study of 
pasture plants (Study 6, p. 56), we found that the weeds of 
Fic. 99. Sun prints of camomile and carrot. 
give the farmer the most trouble. 
petitors. 
The farmer gives them as bad 
planting time. He buries their 
pasture, like the forage 
plants there, are chiefly 
perennials that are able 
to withstand browsing 
and trampling. So, in 
the fields, they must be 
able to mature a crop 
within the lifetime of the 
cultivated species with 
which they are associated. 
Since good plowing puts 
an end to both alike, a 
new start must be made 
from seed. Between plow- 
ing and plowing, there- 
fore, a new crop of seed 
must be matured. Hence, 
the important weeds of 
the cornfield are annuals. 
Perennials are of little 
consequence in tilled fields. 
The weeds that in season 
and habits and require- 
ments are most like the 
crops with which they 
grow, are the ones that 
They are natural com- 
a handicap as possible at 
seed deeply by plowing 
the soil, and at once he plants seed of his own crop at the 
