BOTANY AND VARIETIES 9 



IV — Zea indentata, the dent corns. 

 Sub-groups A, B and C as above. 



V — Zea amylacea, the soft corns. 



Sub-groups A, B and C as above. 



VI — Zea saccharata. 



Sub-groups A, B and C as above. 



These divisions are the result of growing corn in 

 different climates and for different purposes. The 

 division which is of supreme importance commercially 

 is the dent, Zea indentata, and its characteristics will 

 be taken up in detail. The dent varieties have been 

 developed in the central United States as a result of 

 a corn which will give the largest yield of shelled grain 

 adapted for general purposes. Naturally a corn of 

 such general and wide importance has been the subject 

 of great care in development. Unconsciously the corn 

 growers of the past have selected a corn which would 

 mature in the length of season natural to the climate 

 in which it was grown. The character of a corn under 

 such a system of selection slowly changed in response 

 to the effect of climatic and soil conditions. 



As a matter of fact, the history of the development 

 of most of the strains of dent corn now grown is very 

 brief. With few exceptions no record has been kept of 

 the various crosses, and but few varieties have been 

 selected toward a particular type for a special purpose 

 for any considerable length of time. There have been 

 but few systematic attempts at improvement, and the 

 result is that as a rule mongrel or scrub varieties are 

 grown. A few varieties, however, have been carefully 

 selected in accordance with definite ideas as to improve- 

 ment for about a quarter of a century, and have devel- 

 oped certain characteristics distinguishing them from 

 other varieties. In such instances it has been found 

 that if the corn has been selected toward a uniform 

 type, the yield has been increased because of the pro- 



