524 
CHRISTINE E. QUINLAN ON 
pith, where, he says, at least one needle may be seen in every cell. I found no 
trace of crystalline masses in the pith. 
Lignier regards the irregularly thickened pericyclic fibres as an inner lignified 
layer of cortical parenchyma, and the Uniformly sclerotic cells as the bast fibres. 
This can scarcely be correct. Both layers undoubtedly belong to the pericycle, 
as is evidenced by the fact that a well-defined endodermis is seen immediately 
outside. Both kinds of fibres form, in cases where they are developed, a layer 
continuous with the arc of sclerenchyma of the peripheral bundle. Herail states 
that the peripheral bundles, after differentiation from the pericycle, pass out into the 
cortex and remain there. This is not the case in any species of Calycanthus, even 
where the endodermis is not visible, since the sclerotic crest of the bundle is seen 
to be in direct continuity with the layer of pericyclic fibres ; and where the endodermis 
is visible, it is situated on the outer, and not on the inner side of each bundle. 
In the older stem the peripheral bundle, seen in transverse section, resembles in 
shape a wide sector of a circle, with the angle directed outwards. The rounded 
angle is filled with sclerenchymatous tissue ; this crest is connected at each side 
with one of the isolated groups of pericyclic cells. It is in this region that the 
irregularly thickened cells most frequently occur ; they are rarely seen interspersed 
among the ordinary pericyclic fibres, as is the case in C. jloridus. The xylem 
occupies a semicircle immediately within the sclerenchyma, and consists of elements 
like those seen in the younger tissue of the central stele. There are no reticulate 
tracheides with bordered pits, nor wood parenchyma. The phloem forms two wings 
on the inner side, and is separated from the xylem by a Y-shaped layer of cambium 
which gives rise to secondary tissue. The phloem is arranged almost in two strands ; 
in fact, Van Tieghem regards them as separate strands united by a common mass of 
xylem and sclerenchyma. Groups of sclerotic cells occur between the peripheral 
bundles and the central stele, among pericyclar parenchyma. The latter might 
easily be mistaken for cortical parenchyma, were it not that the endodermis stands 
out prominently after treatment with iodine, and completely separates the two layers. 
A series of sections through the node shows the usual ramification of vascular 
strands. In addition, the peripheral bundle of the stem gives off a definite strand 
which passes inside the lateral foliar bundles towards the axillary buds. Here the 
inner bud receives the main strand, and gives off one very minute branch to the 
outer bud. These, later, become the peripheral bundles of the axillary branches, 
and always remain connected with the mother axis at the node. 
The stem of Chimonanthus fragrans differs very little from that of Calycanthus. 
A transverse section of a one-year-old stem shows the usual arrangement of 
vascular tissue. The epidermis bears numerous silicified hairs, which are short and 
stout, and inserted by broad bases between the ordinary epidermal cells. Very few 
show the bend so characteristic of Calycanthus. The cortex is divided into the usual 
two layers, one collenchymatous, the other parenchymatous. Here and there, 
