VI. STEMS 



119. The nature of stems. — The stem is the 

 main axis, or central member of the body of the 

 plant. From its lower end the roots arise and pene- 

 trate the soil, while leaves and reproductive organs 

 are borne on its upper part. Stems are often de- 

 scribed as springing from roots, when they grow 

 from underground stems. This is a mistake, except 

 in a very few instances in which roots are capable of 

 giving rise to stems. 



It is necessary that the roots should be buried in 

 the soil for the purpose of absorbing food, and that 

 the leaves should be held up m the sunlight to 

 enable them to form food ; also that the reproduc- 

 tive organs should be held in a position that will 

 enable them to perpetuate the species. This means 

 that the roots on one hand and the leaves and flow- 

 ers on the other may be separated by iSome distance. 

 The stem is the connecting member, and its bulk and 

 length will vary with the habits and needs of the 

 separate species. 



93 



