THE FILICALES 



287 



foliar gaps, through some of which the cortex and the pith are 

 actually continuous, as is made clear by Fig. 204, representing 

 a small segment of the nbrovascular cylinder. In Fig. 205 is 

 shown a still more magnified view of the marginal region of the 

 stele, and it is here apparent that phloem is present both on the 

 inside and on the outside of the stelar tube. The situation re- 

 vealed by the three figures of the stem of Osmundites skidegatensis 

 shown above 

 makes it evident 

 that in this ancient 

 representative of 

 the group a condi- 

 tion of organiza- 

 tion more nearly 

 resembling that 

 found in our ordi- 

 nary polypodiace- 

 ous ferns was 

 present. The only 

 important differ- 

 ence is furnished 

 by the extremely 

 numerous foliar 

 gaps correspond- 

 ing to the more 

 crowded condition 



of the leaves. This, of course, is not a morphologically important 

 distinction. 



After the description of an osmundaceous fern from the Meso- 

 zoic, the stele of living species of the Osmundaceae may con- 

 veniently be considered. Fig. 206 illustrates the organization 

 of the central cylinder of Osmunda cinnamomea, the cinnamon 

 fern. The fibrovascular tissues in this case are characterized by 

 the same numerous foliar gaps as are found in O. skidegatensis, 

 but the cortex and the pith do not communicate through them 

 as in the Mesozoic type. Further, the phloem in the specimen 

 under discussion, unlike that present in the cretaceous species, 



FIG. 204. Part of the last, more highly magnified to 

 show the leaf gaps. 



