18 Lang —Studies in the Morphology and 
the zone of the outer xylem is thin on the adaxial side: in J the outer 
xylem is more uniform in thickness, and the stele of the branch may be 
regarded as fully constituted. The actual appearance at this level is shown 
in PI. II, Photo 24. Meanwhile, as Text-fig. 4, H, I, J, shows, endodermal 
markings have appeared in a layer of cells between the branch stele and 
the main stele, and this new-formed layer of endodermis has become 
continuous with the endodermis on the abaxial side of the branch stele to 
form the complete endodermis of the latter. By this stage, when the com¬ 
pleted branch stele lies in the cortex beside that of the main rhizome, the 
leaf-gap in the xylem of the latter has closed, and the position of the next 
leaf-trace is evident. The end of the fragment of rhizome is, however, 
almost reached, and the broken stele is in great part decorticated (Text- 
fig-4,J; PI. II, Photo 24). 
It is thus evident that the outer and inner xylem of the branch stele 
are continuous with the outer and inner xylem of the main rhizome, and 
that the endodermis is similarly continuous from the main stem to the 
branch. The same holds almost certainly for the phloem, but on account 
of the difficulty of distinguishing the sieve-tubes, though they could be 
recognized at places in these transverse sections, no differentiation has been 
indicated in the zone between the endodermis and the xylem of the branch 
stele. This zone corresponds to pericycle, phloem, and conjunctive 
parenchyma. Such a branch stele agrees in essentials with the stele of 
a young plant developed from an embryo, and its further consideration will 
be deferred to the next section. 
Two comparative points may be indicated in passing, although they 
will have to be discussed more fully later. Judging by the structure of the 
vascular elements, the stele of the branch would naturally be described as 
centrarch, i. e. as having protoxylem mixed with parenchyma centrally and 
the metaxylem around this. The connexions of these regions of the xylem 
of the branch stele have been clearly seen, however, to be respectively with 
the inner and outer metaxylems of the stem stele. There is thus reason 
for distinguishing inner and outer xylem in the smaller and simpler stele of 
the branch. 
If the connexions of the inner and outer xylem of the branch stele 
(Text-fig. 4) be compared with the large vascular disturbance in relation to 
a vestigial bud that has already been described (Text-fig. 2), a remarkable 
agreement will be found. The bulge of xylem behind the vestigial bud 
was, like the stele of the branch, composed of (a) inner xylem passing out 
through the closing leaf-gap, and (t?) outer xylem continuous with the 
thickened margins of the gap in the xylem. This agreement confirms the 
interpretation of the marked vascular disturbance suggested in the previous 
section of this paper. 
The second branched specimen was an irregular, discoloured, and dying 
