THE STEM 43 



some faint idea of what passes through the mind of 

 an architect who studies Nature. 



5. The water path in plants that have one seed- 

 leaf. Cut a shoot of the Danubian reed — often called 

 " bamboo " (fig. 24), and place the cut end in the red ink 

 as before. Note that the reed has a hollow centre instead 

 of pith. In a short time, you will find the red spots 

 as before, but, this time, not in a ring inside the bark, 

 but scattered all over the solid part of the stem. Note 

 carefully that this is the plan for sap-tubes in all reeds, 

 grasses, lilies, palms and other plants that have the 

 veins running side by side — the plants that have only 

 one seed-leaf. In all plants that have the veins 

 in a network — the plants that have two seed- 

 leaves, we have the root sap-tubes placed as in the 

 vine-shoot. 



6. How palnns and reeds grow. Note, too, that 

 palms and other trees of that class do not grow by 

 adding an annual ring of wood outside the old wood. 

 The new growth is added at the top, and so the stem 

 is nearly of the same thickness at the top as at the 

 bottom. Each year a new bunch of leaves is produced 

 at the top, while the leaves of previous years gradually 

 wither and fall. 



7. Just as the age of an oak tree can be guessed 

 from the rings in the stem, so the age of a palm can 

 often be guessed from the number of rings of leaf- 

 scars on the stem. When the stem is smooth, as in 

 tropical palms, the rings can be counted very easily, 

 but it is less easy with some of the palms of colder 

 lands because the stems may be covered with a thick 

 warm coating of fibre to protect the tree from frost.* 



* A tropical palm can be seen in the Palm House of the Melbourne 

 Botanic Gardens, and in the grounds are many fine palms of a hardier 

 kind. 



