.CORX STIiCCTURE 85 



the fact that most of these nodes bear a shuck or husk, 

 which is only a modified leaf, as will readily be seen by 

 noting that many shucks are tipped with a small leaf-blade 

 (Fig. 34). 



It is supposed that the shank which now bears the ear was once 

 a long branch, and that shortening of the branches occurred both 



Fig. -34. — Ax Ear of Corn ox which Le.\f-el.\des are borxe ox 

 THE Tips of iiaxt of the .Shucks. 



by man's selection and by natural selection. For example, 

 those plants with shortest branches would be the ones most likely 

 to propagate their kind in nature, because these branches would 

 less frequently break ofJ before maturing the seed. For the 

 same rea.=on, selection by man would also tend to preserve the 

 plants with shortest branches. 



