THE VASCULAR CRYPTOGAMS 



45 



arranged in a ring and embedded in ground tissue (see 

 Fig. 21). 



In order to understand the arrangement it is necessary 



sf 



FIG. 21. Transverse section of stem 

 of Male Fern, showing 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 

 FIG. 20. Bundle system of the , ,. , , , 



Male Fern dissected out. st, large diamond-shaped meshes. 



principal steles of the stem ; ac ^ megn corresponds to the 



l.g. leaf gap corresponding to 



the insertion of a leaf ;t, steles base of a leaf; the steles 



passing out into the leaf, bordering the mesh give off 



Magnified. (After Remke.) 



branches, which enter the 



petiole (see Tigs. 19, 20). As the leaf -bases of the Male 

 Fern completely cover the surface of the stern, and no 

 internodes are developed, every transverse section must 

 necessarily be surrounded by the bases of leaves, cut 

 across at various levels, and showing the steles entering 

 them obliquely from the stem (see Fig 21). 



