ORGANS OF NUTRITION. 



99 



the intervals Ijetwcen them internodes. Generally the arrange- 

 ment of the tissue of the stem at the nodes , is somewhat 

 different from that of the internodes ; thus it exhibits a more 

 or less contracted or interrupted appearance, which arises from 

 a portion of its substance being given ott" to enter into the com- 

 position of the leaf. This appearance is most evident in those 

 cases where the internodes are clearly develo])ed, and esjiecially 

 so, if under such circumstances the leaf or leaves which arise 

 encircle the stem, as in the Bandjoo and other Grasses ; in these 

 each leaf causes the formation of a hardened ring externally 

 (fig. 187), and thus produces the appearance of a joint or ar- 

 ticulation, and indeed in rare cases, the stem does readily 

 separate into distinct poi'tions at these joints, in which case it is 

 said to be jointed or articulated. 



Buds. — Under ordinary circumstances, as we have seen, one 

 or more buds arc developed in the axil of every leaf (fig. 191). 



Fig 192. 

 Fig 191. 



Fi(/. lf)l. Brnnch of Oak with alternate leaves and leaf-buds in their 

 axils Fif/. 102. Longitudinal section of the end of a twig of the Horse- 

 chestnut {j'EscuIhs Hijipocastaniim), before tlie bursting of the bud. After 

 Sclileiden. a. The jiitli. h. The wood. c. The bark.. d,d. Scars of 

 leaves of former years, e. e. The vascular bundles of those leaves. 

 /,/. The axillary buds of those leaves, with tlieir sciiles and the vas- 

 cular bundles belonging to them. (/. Terminal bud of the twig ending 

 in a rudimentary flowering panicle. A, h. Scars formed by the falling 

 off of the lowest scales of tlie bud, and above these mav be seen the closed 

 scales with their vascular bundles, i. Medullary mass leading from tlie 

 pith into the axillary bud. 



Tlic a])ex of a stem again, as well as of all its divisions which 

 are capable of further elongation, are also terminated by a 

 similar bud. Each bud, whether lateral or terminal, is pro- 

 h2 



