394 



THE ANATOMY OF WOODY PLANTS 



woody axes with the compound type of foliar ray, if they become 

 sufficiently slender, as in stems of herbaceous texture, give rise 

 to a condition in which the storage parenchyma is entirely lateral 

 to the leaf traces. 



The subject of the organization of rays in typical vines will be 

 made clearer by diagrammatic representation. Fig. 273 illustrates 

 the appearance of decorticated stems of Leea and Vitis in three 



a 



FIG. 271. a, tangential section showing leaf trace surrounded by storage paren- 

 chyma; b, section of leaf trace and ray near the pith. Explanation in the text. 



dimensions. In a is seen a total view of the nodal region of Leea. 

 The traces originate from the axis along a crescentic line and are 

 shown in face view on the surface of the cylinder and in section 

 on its cut end. Obviously the leaf strands are imbedded in foliar 

 rays when viewed from either the superficial or the transverse 

 aspect. In addition to the foliar rays, which in this case are 

 both broad and shallow, there are other narrower rays, which are 

 usually of greater depth. There are also uniseriate rays, diffused 

 throughout the structure of the wood and presenting a rather 

 marked contrast to the two sorts of broad rays. In b is shown a 



