THE VASCULAR CRYPTOGAMS 



45 



see the cut ends of the steles, arranged in a ring and 

 embelded in ground tissue (see Fig. 21). 



In order to understand the arrangement it is necessary 



st 



Yin. 21. Transverse section 

 of stem of Male Fern, show- 

 ing the bases of leaves, st, 

 principal steles of the stem. 

 (After De Bary.) 



to make a dissection, carefully 

 removing the parenchyma and 

 leaving behind the vascular 

 skeleton only. Such a pre- 

 paration is shown in Fig. 20. 

 We now see that the steles 

 form a hollow network, with 

 large diamond-shaped meshes. 

 Each of these meshes corre- 

 sponds to the base of a leaf ; 

 the steles bordering the mesh 

 give off branches, which enter 

 the petiole (see Figs. 19 and 20). As the leaf -bases 

 of the Male Fern completely cover the surface of 

 the stem, and no internodes are developed, every 

 transverse section must necessarily be surrounded by 

 the bases of leaves, cut across at various levels, and 



FIG. 20. Bundle system of the 

 Male Fern dissected out. st, 

 principal steles of the stem ; 

 l.g, leaf gap corresponding to 

 the insertion of a leaf ; t, steles 

 passing out into the leaf. 

 Slightly magnified. (After 

 Reinke. ) 



