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Birbal Sahni. 
whose protoxylems show evident sign of derangement, the one 
opposite the root-strand having become reduced in size. 
It must be pointed out that it is by no means general for a root 
to appear at the level of the bifurcation. On the other hand, several 
may be present at or near the point. It is true a case where a root 
arises at the bifurcation is strongly suggestive of a rhizophore 
arising at a bifurcation of the stem in Sellaginella, as Lachmann 
points out. 
(5) N. ramosa Moore. Herbarium material only was available 
of this species and of N. altescandens. No stolons are borne, but 
the rhizome itself is slender and creeps on the trunks of trees. The 
rhizome frequently gives off side-branches which bear distant 
leaves in two rows, alternately right and left, like the main rhizome 
itself. The branch has an internal structure, and leaf-arrangement, 
identical with that of the main axis, so that only the internodal 
structure and the mode of origin of the branch and the leaf need 
be described (see Text-fig. 7 and PI. IV, fig. 6). 
Text-fig. 7. N. ramosa Moore. Diagram of vascular skeleton to show 
the origin of a branch-trace from the rhizome, and of a leaf-trace from the 
branch. In the natural position the two meristeles of the stem are dorsal and 
ventral, with the gaps right and left. The cut ends of the strands are shown 
black. A-E, stages in the origin of the branch trace ; a-e, corresponding 
stages in the origin of the leaf-trace. Note the great similarity in the 
corresponding stages. At d-e the leaf trace is almost divided into two strands. 
The vascular cylinder at the internode consists of two curved 
strands facing each other (Text-fig. 7, A), but separated from each 
other, and surrounded by a thick layer of sclerenchyma (black in 
the photograph on PI. IV, fig. 6). Each of the strands has its own 
phloem, pericycle and endodermis, and they lie in the dorso-ventral 
plane, the gaps between them being thus respectively on the right 
and left. These gaps are very long, for they overlap in spite of the 
fact that the leaves are more than 2-5 cm. distant on the thin wiry 
rhizome. 
