42 NATURE TEACHING 



are made up of the underground root, and the above- 

 ground shoot bearing leaves, flowers, and fruit Root 

 and shoot are distinct even whilst the young plant is 

 still contained in the seed, being represented there, as we 

 have learnt, by radicle and plumule respectively. 



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 \hzjoints or nodes, and the 

 interval between any two nodes is an internode. Nodes 

 and internodes may be very clearly distinguished on 

 most growing shoots, e.g., roses, elder, privet, etc. 



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 younger. At the apex itself we find the 

 youngest leaves, often more or less closely packed 

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



In the majority of plants the stem is the above- 

 ground portion, the root only being below ground. 

 This, however, is not always the case, and a few of the 

 more important exceptions will be considered later. 



Uses of Stems. 



One of the most important functions of the stem of 

 a plant is to support the leaves and display them to the 

 air and light in the best possible manner for the work 

 they have to do. Careful observations should be made 

 of the arrangement of the leaves on (i) upright grow- 



