248 DOMESTICATED ANIMALS AND PLANTS 



The kernel is generally borne upon an '' ear " emerging from 

 a joint about halfway up the stalk, and the pollen is ripened on 

 a " tassel " at the top ; that is to say, the female flowers are in 

 one place and the male are in another. 



In a few cases, however, stray kernels will be found on the 

 tassel (see Fig. 19), showing the presence of female flowers at 

 the top ; and more rarely will a short tassel be found on the end 

 of the ear, suggesting that the plant has but recently developed 

 from a branching stem bearing, like timothy, both male and 

 female flowers at the extremities. Of course pollen would fall 

 most successfully on the lower flowers, and it is easy to see how, 

 in time, a plant might develop like corn, with nearly all the lower 

 flowers female and nearly all the upper ones male. 



The grain is also exceedingly variable, ranging from the rough 

 kernel of the " dent " to the smooth kernel of the " flint," and 

 from the common starchy field corn to the shriveled sweet corn 

 and the little pop corn of our gardens. 



Another evidence of the newness of corn is its prompt and 

 complete response to selection in almost any desired direction. 

 In this way the color may be changed as well as the size of the 

 plant, the number and height of the ears upon the stalk, or 

 the width and shape of the leaves. Altogether it is an exceed- 

 ingly valuable and unusually interesting plant, and we owe our 

 Indian predecessors much gratitude for its preservation and 

 transmission to us. 



Corn is not a plant well calculated to maintain itself in diffi- 

 cult surroundings or under a very wide variety of hard conditions, 

 so that, all things considered, it is not strange that this plant is 

 not found widely disseminated in the wild. 



First of all, it needs almost ideal conditions for its successful 

 growth, and is easily killed out entirely. Again, the grain sepa- 

 rates with difficulty from the cob. It has neither wings for flight 

 nor means of burial in the ground, neither can it attach itself to 

 the hair or fur of animals for distribution. Moreover, it easily rots 

 in the same climatic conditions that are best adapted to its growth. 



