CEREALS AND FORAGE PLANTS 345 



states, or practically within the drainage system of the 

 Mississippi River (Fig. 17). 



48. Structure of corn. Any one who cultivates corn 

 should know something of its structure, which is quite dif- 

 ferent from that of the other cereals (Fig. 18). There are two 

 kinds of flowers, one containing the stamens and the other 

 the pistil. The staminate flowers form a spreading cluster 

 at the top of the plant, constituting what is commonly called 

 the " tassel." An examination of this tassel shows that it 

 is made up of numerous small flowers, each one of which con- 

 sists of bracts enclosing three stamens whose anthers are soon 

 seen hanging downward, suspended by the long and slender 

 filaments. 



The flowers with the pistils are in a close cluster upon a 

 branch from the axil of a leaf. It is this branch that forms 

 the " cob," and upon it the pistillate flowers stand close 

 together in longitudinal rows. The branch is ensheathed by 

 large bracts, which later form the " husk " that invests the 

 ear. Each flower consists of small bracts enclosing a single 

 pistil, whose long, thread-like style forms the so-called " silk." 

 It is the silk that receives the pollen from the stamens, and 

 through the silk the pollen tube carries the male cell to the 

 egg. In this way fertilization occurs, and as a consequence 

 the grains begin to develop and later the mature " ear " is 

 formed. 



The danger from drought occurs when the pollen is flying, 

 for at that time the silk must be moist to receive the pollen 

 and to start the growth of the pollen-tube. Since four or 

 five days are consumed in fully pollinating a single ear, which 

 means that each silk must catch and hold some pollen, it is 

 evident that a drying wind, or even dry air, will endanger the 

 process. This is the most critical period for the corn crop, 

 for blasted silk means failure of fertilization. 



49. Cultivation of corn. In the cultivation of corn, only 

 general principles can be mentioned here. There are many 



