184 



THE MARATTIALES 



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 m the 

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

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



Fig. i68. 



A, B. Two sections above level of stem apex of a young sporophyte of Kaulfussia of about same age as that shown in fig. 167. 

 C-J. Sections taken lower down from same series, m , mucilage ducts. 



K. Central bundle of section J. X140. 



L. Part of the bundle of section H, more enlarged. G, F, I, J, show only the central region of the sections. 



Ophioglossum than it is like the other Marattiaceae. 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 Helminthostachys (fig. i68, K^. 



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

 root near its base, a large lacuna which recalled the similar lacuna found in the 

 first internode oi Helminthostachys. 



