42 NATURE TEACHING. 



CHAPTER TIL- THE STEM, 



1. The stem, as opposed to the root, is 

 that portion of the plant which bears the 

 leaves and flowers. Stem and root are, as we 

 have seen, distinct even whilst the young 

 plant is still contained in the seed, being 

 represented there by plumule and radicle 

 respectively. 



2. The leaves are usually arranged on 

 the stem in a definite manner ; the places on 

 the stem from which the leaves spring are 

 known as the joints or nodes and the interval 

 between any two nodes is .an internode. Nodes 

 and internodes may be very clearly distin- 

 guished on a piece of sugar-cane stem. 



3. On examining any leaf-bearing stem 

 it will be noticed that the oldest leaves are at 

 the base, and that as we approach the summit 

 of the stem the leaves get younger and young- 

 er. At the apex itself we find the young- 

 est leaves, often more or less closely packed 

 together to form a leaf -bud. Similar but small- 

 er leaf-buds are usually to be found lower 

 down the stem, situated just above the place 

 where a leaf joins the stem ; it is very general 

 to find one to each leaf. 



4. In the majority of plants the stem is 



