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Anatomy of the Ophioglossaceae. 1. 
the band of secondary xylem continuous with the centrifugal primary 
xylem, the cambial activity had been resumed, and a further zone of 
secondary xylem had been formed This was in great part parenchymatous, 
but numerous tracheides had been developed in the radial rows of cells 
produced from the meristem. This resumption of secondary growth must 
be placed in relation to the development of the branches. 
The general vascular relations of the branches to the main axis will 
be understood from Text-fig. 14. At the level where the series begins 
(a) one leaf-trace is nearing the periphery of the cortex, and the position 
of the vestigial bud in relation to this leaf is indicated by the slit in the 
next diagram. A second leaf-trace has departed leaving a wide gap in 
Text-fig. 14. Series of transverse sections of the fourth branching specimen. Description in text. 
the stele, and opposite the gap is the vascular supply for the first branch. 
The xylem for the branch is in part connected with the additional secondary 
xylem, and in part appears to come from within the leaf-gap. In B the 
attachment of a root-stele by one side of this gap is seen, and a root was 
attached on the other side between the levels of A and B. The stele is 
imperfect in the neighbourhood of the first branch, and the latter cannot be 
followed further. This section (b), however, shows the first indication of 
the vascular supply to the second branch. The leaf-trace subtending this 
branch still forms part of the complete vascular ring of the main stele, but 
is distinguishable by the outward slope of its tracheides. Internal to the 
xylem of this trace a group of tracheides has arisen at the periphery of 
the pith. This group of tracheides increases in size as the trace prepares 
