ANATOMY OF STEMS 



221 



XLjIem rat^ 



perforated ena 

 wall of vessel 



vessels 



fiber -tracheids 



Fig. 56. Tangential section of a small portion of the wood of a tulip tree {Lirio- 

 dendron iuUpifera). This is a plane section except that the end walls of the vessels 

 have been shown in perspective in order to indicate their structure clearly. Most of 

 the vessels and fiber tracheids show in sectional view, but a few show as the surface 

 view of the tangential wall. Surface and sectional views of bordered pits show in the 

 vessel walls. Simple pits show in the end walls of ray cells and between ray cells. 

 Half-bordered pits show between vessels and ray cells. Adapted from a drawing by 

 L. G. Livingston. 



