452 MR. W. C. WORSDELL ON THE 
Adult Plant. 
The middle portion of a stem, which was from 6-8 inches in 
diameter, was submitted to me for investigation. It offered, 
however, no specially noteworthy feature in its structure. lt 
was found to be of the type possessing but a single vascular 
cylinder. The only two characters of any importance are: the 
incomplete cauline strand in the cortex, and the peduncular bundles 
of the pith. 
The cortex is bounded on its outermost side by periderm con- 
sisting of a narrow outer rim of cork and a very thick inner layer 
of phelloderm. The latter is built up of small square cells arranged 
in radial rows continuous with those of the cork-cells. Inter- 
spersed amongst these are branched mucilage-canals. An isolated 
case was observed in one part of this tissue, and nowhere else, 
of a curious structure of secondary character running vertically 
or obliquely, and consisting of two strands, each composed of 
short, angular, isodiametric, reticulate tracheides and thin-walled, 
elongated, colourless cells, all these elements being cut off by a 
cambium. The xylems of the two strands are directly opposed 
to one another, the wide parenchymatous tissue separating them 
being sometimes bridged by tracheides. In some places only one 
of these strands was present, the other having died out, leaving 
no trace, or its former position still traceable by a few cambial 
divisions in the parenchyma. An outgoing leaf-trace bundle 18 
seen to be connected to one of these strands at one point. 
All the cells of the cortex and pith are crammed full of starch- 
grains, which are very minute and irregularly angled. No girdle- 
leaf-trace bundles are seen, although these may have existed at an 
earlier stage of the plant’s life and been subsequently cut off by 
the advancing periderm. — All the leaf-traces observed run 1n à 
fairly direct radial direction to the central cylinder. In one 
place two contiguous leaf-traces running straight to the vascular 
ring are united by a curved connexion, which, running out from 
one, bends back and joins the other. 
The xylem of the central cylinder forms a rather narrow zone 
divided up into narrow segments separated by medullary TAY 
The tracheides composing the wood have a very irregular course; 
as seen in a tangential section of the wood they bend and curve 
. . . . . k throug 
about in every conceivable direction, forming a networ to 
whose meshes run the medullary rays. Their course appe n 
be far more irregular than is that of the tracheides in the ste 
