86 



ENDOGENOUS STEMS. 



plant is also said to be an exception to this rule. The circular figure of the 

 stem is due to the somewhat even distribution of the leaves around the trunk ; and this 

 will be the most perfect when the tree has grown apart from others, and where it is 

 freely exposed on all sides to the influence of light. 



The wood of plants is not composed exclusively of woody tissue, but with that 

 structure is bothrenchym, or dotted tissue and ducts, in greater or less abundance. This, 

 as before mentioned at page 17, is more particularly the case in fast-growing plants. 

 The diagram on page 85, of an exogenous stem, shows how largely pitted tissue is 

 intermingled with the wood. 



Fig. 143, representing a Palm forest, and some of the leading characters of endogenous growth. 



Endogenous Stems. We now proceed to a description of stems which will be 

 less familiar to our readers, and which can usually be examined in museums, or as dried 

 plants only. These are almost peculiar to tropical regions, and are exclusively so if we 

 refer to wooded plants of considerable size. The giant representative of this class is 

 the Palm tree, with its wonderful utility and beauty. 



The class is represented in this country, and in almost all cold climates, by plants of 

 lesser growth, and more particularly by the grasses ; yet, with the exception of the 

 direction of the veins of leaves, they afford but unsatisfactory indications of the peculiar 

 structure of the plant. The most ready illustration will be found in the common Cane 

 and Bamboo ; and these will suffice for a sufficient inquiry into this subject. 



The term "endogenous" signifies to grow inwardly, and is explained by stating 

 that the bundles of wood sent down from the leaves do not range themselves in layers 



