128 The Principles of Vegetable -Gardening 



the fact that all the kernels of the ear were used, thereby largely 

 obliterating any difference that might exist between the butt, 

 the middle and tip kernels by introducing all the intermediate 

 variations. 



Abnormal seeds, being usually imperfectly formed or not 

 fully developed, possess a low vitality as a rule. The "tassel 

 corn " affords an illustration in point ( Sturtevant) : 



Abnormal corn produced on the tassel 



No. kernels No. Per cent 

 Variety planted grew grew 



White Pop Corn .24 7 29.2 



Waushakum Flint 84 19 22.6 



" " 84 21 25 



11 55 16 29.1 



" " 24 . 18 75 



Blount's Prolific 24 11 45.8 



" 24 6 25 



Imperfect fertilization is often the cause of low 

 germinative vitality, or even of its absence. The seed 

 may develop to the full size and ordinary appearance 

 and yet entirely lack the embryo. Nageli considers 

 the following degrees of sterility of seeds due to 

 imperfect fertilization : a small and imperfect fruit 

 with empty seeds ; ordinary fruit with empty seeds ; 

 ordinary or normal fruit and apparently good seeds 

 but which have no embryo ; ordinary fruit with seeds 

 bearing a minute and imperfect embryo which cannot 

 germinate. This absence or imperfection of the 

 embryo is in some cases the cause of lightness of 

 seeds, although lightness is, no doubt, oftener due to 

 a deficiency in nutrient matter. 



The color of the seed appears to exercise no influ- 



