BOTANY AND VARIETIES J 



tific basis. He has divided the polymorphic species 

 (Zea Mays) into a number of groups which, on ac- 

 count of their well defined and persistent characters, 

 may be considered as representing specific agricultural 

 claims, and may properly receive specific nomenclature. 

 The grouping that he has adopted is founded upon the 

 internal structure of the kernel for our cultivated va- 

 rieties and the presence of a husk to the kernel in the 

 assumed aboriginal form. Arguments in favor of the 

 specific claims for these groups are based primarily 

 on the convenience thus attained, secondarily on the 

 absence or rarity of intermediate or connecting forms, 

 so far as our present data extend, and also on the 

 antiquity of separation. Each race is characterized by 

 numerous varieties, and these freely cross-fertilize. 

 The relative differences between the races are clearly 

 seen by splitting the kernels. These species groups as 

 established by Dr Sturtevant are: 



Zea tunicata, the pod corns. In this group each 

 kernel is inclosed in a pod or husk, and the ear thus 

 formed is inclosed in husks. 



Zea everta, the pop corns. This species group is 

 characterized by the excessive proportion of the cor- 

 neous endosperm and the small size of the kernels and 

 ear. The best varieties have a corneous endosperm 

 throughout. This gives the property of popping. 



Zea indurata>, the flint corns. A species group 

 readily recognized by the occurrence of a starchy endo- 

 sperm inclosed in a corneous endosperm at the sides 

 of the kernel, the starchy endosperm extending to the 

 summit. By the drying and shrinkage of the starchy 

 matter the summit of the kernel is drawn in or together 

 and indented in various forms. In different varieties 

 the corneous endosperm varies in lengfth and thickness, 

 thus determining the character of the indented surface. 



