1 84 THE ANATOMY OF WOODY PLANTS 



prevails almost universally in the organization of their woody 

 cylinder. 



It will now be advantageous to consider those angiospermous 

 stems which are united in habits under the forms known as vines 

 and herbs. In this connection it will be well to restrict our atten- 

 tion to the typical representatives of the two groups, since plants 

 which are not clearly marked either as herbaceous forms or as 



FIG. 137. Diagram of the organization of the stem in Leea, a shrubby tropical 

 representation of the Vitaceae. 



vines are of very little importance in the present connection. A 

 general feature of the forms included under the two headings here 

 discussed is the presence of large rays of the oak type. This 

 situation has long been recognized in the case of the particular 

 modifications of the stem to be elucidated in the present and in a 

 following paragraph. The vine type may well stand first, as it is 

 nearer the ordinary woody perennial condition of organization 

 than that found in herbs. Fig. 137 illustrates the organiza- 

 tion of the woody cylinder of Leea, a shrubby tropical genus 

 belonging to the Vitaceae. Here we find very obviously both 



