OF THE BRITISH COAL MEASURES. 81 
passes out between the two leaf-trace strands; in this case its connection 
with the wood of the stem is clearly shown. The wood is here more developed 
on the leaf-trace side than on the other, but is very irregular and many of 
the tracheides are cut longitudinally. 
Tt is evident, from the last two sections, that a row of adventitious roots 
was given off between the two bundles of the leaf-trace. This agrees with 
the evidence from a longitudinal section (W. 1915 G) previously figured and 
described *. Here three roots are seen in a vertical series; just as in the 
transverse sections the pericycle “has undergone an enormous thickening, 
with tangential cell-divisions, around the bases of the roots." The anomalous 
development of secondary wood in the same region was also mentioned 
and compared to the “réseau radicifére” of Van Tieghem. Ina parallel 
longitudinal section t of the same portion of stem, the roots are missed, but a 
leaf-trace bundle is shown in the corresponding position. This was doubtless 
one of the two bundles flanking the row of roots, as shown in the transverse 
sections. The longitudinal sections show clearly that the local hypertrophy 
of the pericycle had nothing to do with a leaf-base, for the leaf-trace strand 
shown is still running almost vertically and not bending out. 
For the reasons already given, I have no doubt that the two bundles 
shown in the transverse series belong to the same trace; their wide 
separation may be due to the presence of the roots between them, and it is 
possible that they may have again converged before entering the base of 
the leaf. 
Throughout the series no other trace-bundles are given off. The seven 
sections, considering the date at which they were cut, would represent a 
length of quite an inch, so we may infer that the leaves were widely spaced 
with long internodes. 
Specimen 2 (P1. 4. fig.13; S. 445), a smaller stem (about 9 x 8 mm.), likewise 
shows two bundles only in the transverse section; they are both at one 
end of the compressed stele, and.the interval between them is 16mm. They 
lie just outside the wood of the stele. No other trace is given off in the 
three sections of this specimen 1, all of which show the same two bundles. 
Between them there are two marked protrusions of the secondary wood, 
which appear to be composed of short pitted tracheides. These are evidently 
connected with the insertion of adventitious roots, which are clearly shown 
in one of the sections (Q. 64). Two of the roots are seen side by side; there 
may have been a double row, as was possibly the case in the previous specimen 
also. A huge mass of ill-preserved tissue encloses the roots and bundles. 
* Williamson & Scott, 1895, p. 757, pl. 27. fig. 28. 
T W. 1915 R. 
t The order from below upwards seems to be: S. 445, Q. 64, W. 1915 H, but as the two 
latter are very oblique it is difficult to determine. 
