THE STEM. 1 



tion iiTul enlargement of tlie culls throughout its whole length, 

 but )i8 it gets older elonj^ation for a considoruble jjortion of the 

 lute 'node ceases, and fiiuilly there comes a time when the culm 

 is incapable of further elongation. If taken in hand when young, 

 and i)ro])crIy shaded, a stem may be made to grow to an almost 

 indefinite length. The lower portion of an internodo of most 

 grasses, the part within the leaf-sheath, renniinssoft and continues 

 to grow for a considerable time after the upper and nmin portion 

 has lost this power. 



Via. 5.— A cross-section of flhro-vasciilar bundle of Indian corn : a, Hide of bundle 

 looking toward tlie circumference of tlie stem ; i, side of bundle toward the center of 

 stem ; p, tidn-walied cells of fundamental tissues of stem ; {/, (/, larne pitted vessels ; 8, 

 spiral vessel ; r, one ring of an annular vessel : I, air cavity formed by the breakins 

 apart of the surroundinR cells ; i\ i\ latticed cells, or soft bast, a form of sieve tissue. 

 X 530.— (After Sachs ; notes after Bessey.) 



