292 MR. HENFREY ON THE ANATOMY OF THE STEM OF VICTORIA REGIA. 
for the roots chiefly from the more delicate fibres running horizontally around 
the outer part of the central region, Plate XX. figs. 3, 4 h. The bundles for the leaf 
run out as large fibres, independent of each other, and imbedded in firm cellular 
tissue continuous with that of the cortical layer ; they form a group which presents a 
triangular section when cut across, Plate XX. figs. 7? 8 a. The vessels for the root- 
bundle are all collected into a somewhat cylindrical cord (Plate XX. figs. 7? 8 h), where 
they pass through the outer part of the cortical layer, which cord runs parallel to 
and just below the collection of fibres for the leaf; it subdivides quite close to the 
points of attachment of the roots. 
It has been stated that plates of the firm cortical layer run through the spongy 
substance ; these form buttresses, as it were, and cross-walls running between and 
connecting the processes which give origin to the leaves and roots, in the manner 
shown in the drawing (Plate XX. fig. 7), which is a plane 'projection of the cut surface 
of a portion of the cylindrical stem, showing the cut ends of the vessels of the leaves 
and roots (Plate XX. fig. 7, a, b), as also of those of flower-stalks (Plate XX. fig. 7, c) ; 
all of which are connected together by plates of firm tissue, the edges of which are 
shown in the section, Plate XX. fig. 7,ff- 
The vascular bundles of the flower-stalks run out from the vascular region in the 
substance of these plates, having no proper branch-like process such as we find sup- 
porting the leaves. It is remarkable, as is seen in the section, that the flower-stalks 
lie nearer to the leaf above them than to those to the axils of which we must suppose 
them to belong. 
The apex of the stem, with the delicate structures of the terminal bud, was so 
much decayed as to prevent satisfactory examination of the course of development 
of the vascular bundles ; but so far as I could judge from the investigation of the 
sound portions of the stem, it is analogous to that of the Monocotyledonous rhizomes 
formed by the continuous development of a terminal bud, without the elongation of 
the internodes. The non-development of the internodes produces a prevalence of 
horizontal direction in the vascular bundles, very little vertical growth occurring to 
produce a perpendicular elongation of these structures. It is evident from the rela- 
tive condition of development of the vascular bundles in the different parts of the 
stem, that the order of growth is the same as that in the Monocotyledons, and that 
the central bundles are the oldest, the outer and upper the youngest, and that the 
increase of thickness of the stem, which takes place only up to a certain point, is 
produced by expansion of rudimentary organs, chiefly in the outer part of the central 
vascular region. 
The vascular system is exceedingly simple in its nature. There exists no analogue 
to wood or liber, the bundles are exclusively composed of vessels of large size, 
chiefly of spiral vessels with two or three parallel fibres, but also with reticulated 
and partially annular vessels, all unreliable. These vessels are surrounded by cellular 
tissue composed of longitudinal rows of small, oblong cells, with strong but thin 
