184 



III! MARATTIALKS 



than it is in the roots. In the upper region of the stem the leaf traces are further 

 apart, and as the number increases a cross-section of the stem shows a circle 

 of separate bundles closely resembling the arrangement in Ophioglossum. The 

 central "commissural" strand, which is found in the adult stem, had not developed 

 in any of the young sporophytes I examined and evidently arises much later in the 

 history of the sporophyte than it does in the other Marattiacea?. In this respect, 

 as well as in the arrangement of the bundles themselves, Kaulfussia is more like 



Fig. 168. 



A, B. Two sections above level i>f stem apex of .1 young sporophyte <>f Kaulfutiia ol about same age i tli.it shown in fij;. 167. 

 C-J. Sections uikrn lower down from sanu- series. m t mucilage ducts, 



K. Central bundle of section ]. X140. 



I.. Part til tin- bundle *>l section Tl, more enlarged. G , V , I, |. show only tin- central region of tin- secti ins. 



Ophioglossum than it is like the other Marattiacea'. In the intermediate condition 

 between the single solid stele found in the very young stem and the entirely separated 

 leaf traces of the older rhizome, there is a transitional condition with a "siphono- 

 stele," very much as in Helminthostat hys (fig. [68, A ). 



In one very young sporophyte there was found, in the cortex of the primary 

 loot neat its base, a large lacuna which recalled the similar lacuna found in the 

 first internode of Helminthostachys. 



