Bower. — Studies in the Phytogeny of the Fi lie ales. 283 
is shown of the natural size. The leaves are at considerable distances 
apart, so that in transverse section the leaf-gaps do not overlap, and trans- 
verse sections of the parts lying between them would show the complete 
solenostele. It may be noted that in this case the adventitious buds are 
absent from the leaf-bases. 
It has been pointed out that roots and adventitious buds are borne by the 
axis. The attachment of the roots is shown in PI. XXXIV, Fig. 11. Their 
vascular supply comes away from the outer margin of the stele in the usual 
way. The adventitious buds are placed with regularity below the leaf- 
bases. Frequently there is one at the base of each, but their presence is 
not constant. In order to trace the vascular connexion of the bud and its 
related leaf, sections were cut transversely to the parent shoot, as in Fig. 12. 
Of these (i) is the lowest ; it shows a foliar gap of a preceding leaf just 
closing, while almost opposite the thinning out and extension of the stele 
is beginning preparatory to the departure of the next trace. But already 
the related bud (b) is traversed, though the section was below the level of 
its vascular supply. In Fig. 12, ii, the bud is traversed in median section, 
and it is seen that not only does the vascular tissue extend directly out into 
it, but the sclerenchyma also ; in fact, the vascular tissue of the bud arises 
as a diverticulum of that at the base of the related leaf. Closely above it, 
as shown in Fig. 12, iii, the leaf-trace itself comes off in the usual way. 
These results were checked by tangential sections, as shown in Fig. 13. Of 
the sections there shown (i) is a transverse section of the bud close to its 
base, showing its solenostelic structure, with numerous roots. A tangential 
section just below its insertion is seen in (ii), which shows the continuity of 
the sclerenchyma and pith of the main axis with that of the bud. It is 
also seen how the vascular supply of the bud arises from the leaf-trace 
strand itself. A section still lower is seen in (iii), where the ring has 
widened out, and merged into the curved strand of the trace. 
It is thus seen that the adventitious buds may be solenostelic from 
the first. It is not improbable that small and weak runners may be proto- 
stelic at their base, but none have been observed. Unfortunately the 
youngest plants available from those collected in the open forest showed 
already the solenostelic structure ; and as the cultures from spores did not 
come through to the formation of sporelings, the ontogenetic origin of the 
solenostelic structure in the plant must for the present remain in doubt. 
PL XXXII, Fig. L, represents the vascular skeleton of a shoot of moderate 
size, showing the relation of the supply to the adventitious buds to that 
of the leaves. In this case most of the leaves bear an adventitious bud, 
but in some cases the bud was absent. 
As regards the details of structure, the solenostele is of a very usual 
type. It is limited on either side by an endodermis with brown coloured 
walls, succeeded by a pericycle of two or three layers, and the broad band 
