8 ROYAL SOCIETY OF CANADA 
Immediately external to the xylem, the phloem consists of several 
rows of medium sized, thin-walled cells containing conspicuous nuclei, 
but devoid of starch. In longitudinal section these cells are found to be 
short cylindrical, and the nuclei become much more prominent. (Plate 
IL, fig. 5.) This tissue is succeeded by a layer of large, rather thick- 
walled sieve cells of very regular form, but variable in size and shape, 
often exceeding the largest xylem element. (Plate II., fig. 4.) 
Opposite the terminations of the rays, this zone broadens out radially 
and projects into the ray like a blunt wedge, after the manner described 
by De Bary for Osmunda.! (Plate IT. fig. 4, and Plate VI. fig. 11). 
External to the sieve cells, the phloem again becomes very thin 
walled, the cells contain prominent nuclei, are devoid of starch and are 
radially narrow, being tangentially elongated (Plate IV., fig. 7) in a 
manner quite similar to what occurs in Todea (Plate VI., fig. 12), and 
much more so than in either of the Osmundas studied. (Plate VI, 
fig. 11.) 
The Endodermis.—The transition from the outer phloem to the sur- 
rounding parenchyma zone, occurs without any abrupt transition other 
than that which appears in the passage from radially narrower to radi- 
ally broader cells. (Plate IV., fig. 7.) In other words, there is no 
separate and well defined endodermal layer such as occurs in Osmunda 
regalis and other ferns (Plate VI., fig. 11), but the transition is in all 
respects comparable with that which may be observed in Todea barbara. 
(Plate VI., fig. 12.) 
Parenchyma zone or inner cortex.— Immediately external to the 
stele is a zone about 3 mm. thick, and thus with an external diameter of 
about 25 mm. (Plate I., fig. 2.) It probably represents a colourless 
tissue, and consists of rather large, thin-walled elements (Plate IV., 
fig. 7), in many of which starch may be seen—quite enough to indicate 
that the tissue as a whole was filled with this material as in Osmunda. 
The starch appears in the form of large grains somewhat highly 
carbonized, and in the figures (Plate II., fig. 3 and Plate IV., fig. 7) it 
gives a dark colour to the individual cells. The tissue as a whole 
presents but little alteration, and from the comparatively small amount 
of carbon present, it was evidently a tissue presenting but little, if any, 
modification in the original plant. An exactly similar and equivalent 
zone is met with both in Todea and in the Osmundas (Plate VI, fig. 
i1), and in the latter particularly the entire structure is filled with 
starch. 
This region is traversed by few leaf traces (Plate I., fig. 2), since 
it is into this part of the stem that they are first given off from the 


1 Comp. Anat. of Phan. & Ferns, 347. 
