12 ROYAL SOCIETY OF CANADA 
enlarging upward. The stumps of the old stipes are seen to overlap 
laterally to a limited extent, while the older overlie the more recently 
formed in such a manner as to explain the upward enlargement. It 
is also seen that the stipes arise chiefly from the under side of the 
rhizome? (Plate V., fig. 9 shows this aspect), from which position 
they turn upward. On the upper side of the rhizome the roots have a 
diameter upwards of 1 X 2 mm., slightly smaller than in the fossil. 
These organs are very numerous, and form an extensive mass 
which serves to completely conceal the stumps of the stipes arising 
from the same side of the rhizome. This distribution of roots and 
leaves is exactly represented in the fossil, from which it is pos- 
sible to determine the position of the latter in growth, and to distinguish 
the superior from the inferior surface. The stipes are given off from the 
under side of the principal axis at an angle of 15°, and from the upper 
side at an angle of 28°. In O. cinnamomea, on the other hand, the 
angle is much less—ten degrees—and the same for both sides. A further 
examination of O. regalis shows that, taking the divergence of the stipes 
from a median line drawn on the under surface of the rhizome, the aver- 
age is 15°, which is just that obtained from the longitudinal section. 
From this it may be inferred that the divergence of the stipes in the 
fossil as measured on the surface, is the same as would appear in longi- 
tudinal section, and therefore, the external angle of 10° as obtained is 
the true angle of divergence from the central axis. This being admitted, 
it then appears that in this respect, the fossil approaches O. cinnamomea 
much more nearly than O. regalis. 
A transverse sect:on of the rhizome (fig. 2) shows (1) a conspicu- 
ous pith, (2) the stele, (3) a parenchymatous zone penetrated by few 
leaf traces and corresponding to the third region in the fossil, (4) a broad 
zone of sclerenchyma penetrated by many leaf traces, and represented 
in the fossil by portions of a highly carbonized zone, (5) a region where 
the stipes are loosely held together by soft tissue—a region not repre- 
sented in fig. 2, but appearing in two of the fossil specimens in the 
form of carbonized surface areas of limited extent. 
The Pith.—The pith is about 1 mm. broad. This is approximately 
the same as in O. cinnamomea (1°25 mm.), but only one-thirteenth the 
diameter of the same structure in the fossil, from which inferences may 
be drawn respecting the relative dimensions of these plants. The cells 
are rather large and thin-walled, and are very commonly found to con- 
tain an abundance of starch. Within limited areas, the cells are thick- 
walled, thus forming groups of dark coloured sclerenchyma. 

? The eccentricity of the central axis of Osmunda relative to the exter- 
nal portions of the rhizome, has been incorrectly interpreted by Carruthers as 
due to unequal wearing of the parts. (Quart..Jrnl. Geol. Soc., 1870, 349.) 
