12 BOTANY OF CROP PLANTS 



tious roots will appear at the cut surface, and by develop- 

 ment, form the characteristic root system of the plant. Some 



ground linj 



Fig. 3. — In spite of the fact that the grain of wheat was planted at too great a 

 depth, the permanent roots were formed at about I inch below the soil surface. 



leaves will even develop adventitious roots from cut or 

 wounded leaf veins. This is true of such leaves as begonia. 



