386 BOTANICAL GAZETTE | DECEMBER 
Claytoniana the radial markings are generally not as distinct as 
in the rest of the species studied, and the cells are reduced in 
size in comparison with those of the layers in contact (fig. 8, ¢). 
The contents in this species, too, are meager, consisting of 
granular protoplasm, a nucleus which as a rule stains a deeper 
red with saffranin than those of surrounding cells, and a few 
starch granules as shown by treatment with iodin solutions. 
Sometimes the endodermal cells of O. cinnamomea are likewise 
apparent by the lack of contents, in contrast to the heavily-laden 
cells, both ectad and centrad. Generally in this species, as in 
the remaining ones, 7. superba excepted, the cells are filled with 
tannin, so that the endodermis stands out very distinctly. 
The pericycle is entirely parenchymatous and consists of 
several layers—in O. Claytoniana and Todea of two or three, in 
O. cinnamomea of three or four, and in O. regalis of one to three. | 
The cells are elongated, cylindrical, provided with large nuclei, 
and filled with finely granular contents, part of which is starch. 
Haematoxylin imparts to this tissue a light blue color. Tangen- 
tial sections show that the orientation of the cells is very irregu- 
lar (figs. 3 and 9, p). Immediately opposite the point of origin 
of a leaf trace, and for a short distance below, the long axes of 
the cells run parallel with the long axis of the stem, but for the 
most part in the remaining regions of the stem there is consid- 
erable disturbance, though only in tangential planes. This dis- 
turbance is commonly so marked that the long axis of the cell is 
at right angles to the stem axis, and between this and the paral- 
lel position there is every gradation. Therefore in transverse 
section these cells are either round or more or less tangentially 
lengthened (jig. 8, pf). This variation in orientation is of 
interest, as it is connected with a similar phenomenon in layers 
lying nearer the cauline axis, namely in the phloem region. 
XYLEM.— Before dealing with the phloem, however, it will 
be convenient to describe the xylem. The wood elements are 
of two kinds, namely, small ringed and spiral elements consti- 
tuting the protoxylem, and scalariform tracheids which are of 
later development constituting the metaxylem. Occasionally a 
