34 ROYAL SOCIETY OF CANADA 
quency of occurrence, closely duplicate similar features in Todea. 
(Plate VIIL, fig. 4.) 
The protoxylem is well preserved, and it appears as a well defined 
layer on the ventral side of the stele. (Plate IX. fig. 6.) The elements 
are narrow and rather thin-walled, and they form a layer of very 
unequal thickness. The secondary xylem is represented by broad, not 
very thick-walled elements which lie within a single row. (Plate IX., 
fig. 6.) 
Longitudinal. (Plate X., fig. 8.) The longitudinal section was 
most fortunate, cutting through the stele in the dorsal half so as 
to expose nearly all the component elements. This section also 
shows the epidermal tissue to be wholly wanting. The outer cortex 
consists of rather narrow, fibrous sclerenchyma cells which gradu- 
ally diminish in length and increase in breadth until they pass into 
the structure of the inner cortex (Plate XI., fig. 9) where the ele- 
ments are fusiform. The inner cortex terminates in a narrow zone 
of fibrous sclerenchyma elements, precisely as in Todea, and 
although the details of structure are not very clearly distinguish- 
able, there seems little reason to doubt that this is the equivalent 
of the similar sheath in Todea, and that it represents the 
sclerenchymatous zone replacing the special endodermis, as so 
commonly occurs in the Osmundas. Within this sclerenchymatous 
sheath is the broad, vacant region formerly occupied by thin-walled 
parenchyma, and the great abundance of mucilage located here, now 
becomes much more apparent than in the transverse section. The 
mucilage zone is inwardly limited by the remnant of the phloem, and 
this is succeeded in turn by the xylem. The section appears to have 
cut through the xylem at such a point as to expose the inner edges of 
the scalariform vessels which appear to form the principal elements, 
(Plate XI., fig. 10) but at one point it traverses the protoxylem which 
is shown as very narrow tracheids with exceedingly close spirals, so 
as to resemble scalariform structure. The succession of tissues as 
exposed in the longitudinal section, is therefore as follows :— 
1. Cortex. 
(a) Hypodermal, fibrous, narrow-celled sclerenchyma passing into 
(b) The inner cortex composed of large-celled, thin-walled, fu- 
siform parenchyma with an abundance of mucilage cells. 
. The sclerenchymatous sheath replacing a special endodermis, and 
composed of slender, fibrous sclerenchyma as in Osmundas 
of recent times. 
3. A broad zone of parenchyma from which the structure has been 
removed by decay—now occupied by globules of mucilage. 
[au] 
