472 Sinnott. — Some Jurassic Osmundaccae from New Zealand . 
The structure of the stem and leaf-bases of both sets of material is 
very similar. The stele is of moderate dimensions (5 mm. to 8 mm. in 
diameter) and surrounds a true parenchymatous pith. This pith is 
excellently preserved, and is uniform in character in the Kawhia specimen, 
but almost structureless in those from Waikawa. In the latter material, 
however, there are in the pith numerous strands of xylem, elliptical in 
shape, with an exarch protoxylem group at each end (Figs. 2, 3, 5, and 6). 
There may be as many as four of these in a single section. They are 
precisely similar to the typical diarch root bundles which are distributed 
throughout the cortex. About each strand is a definite, sharply limited, 
and well-preserved parenchymatous cortex (Figs. 5 and 6). There is little 
doubt that we are here dealing with roots which in some way have managed 
to enter the pith of the stem. 
That such an interpretation is the correct one is further emphasized by 
the occurrence of a similar condition in living species. Fig. 8 shows 
a section of the stem of Osmunda cinnamomea with a root obviously present 
in the pith. Fig. 7 shows the same stem a little further along, where 
a dichotomy occurs, and makes plain the fact that the root has invaded the 
pith from the cortex through the branch gap. In a similar way, probably, 
the roots in our fossil were able to make their way into the pith. 
There are no positive indications of internal phloem or endodermis. 
The external phloem is normal in structure and distribution. 
The leaf-gaps in the xylem are extremely narrow, and in the Waikawa 
specimen, where the xylem has been more or less compressed and distorted, 
they often appear to be absent. In the Kawhia material, however, which 
has suffered little disorganization, it is evident that leaf-gaps, although very 
narrow, are invariably present (Fig. 1). As is the case in some other fossil 
Osmundaceae, and in certain living species as well, the gap is not always 
complete immediately at the departure of the leaf-trace, but becomes so 
before the trace has passed very far into the cortex. 
The leaf-trace is the typical elliptical monarch strand of the family. 
The protoxylem is often mesarch in position for a short distance, but soon 
becomes endarch. 
The base of the petiole is without a broad stipular wing (Fig. 4). Its 
vascular bundle is surrounded by a circular ring of sclerenchyma, and there 
is a large island of the same tissue on each side of the ring, as well as 
several other smaller spots. The bundle is the typical single arch, and has 
a large patch of sclerenchyma inside each lateral bay. 
The specimens from the two localities are very similar, and they 
display a close agreement in structure with 0 smundites Dunlopi , a species 
described by Kidston and Gwynne-Vaughan ( 1 ) from Gore, New Zealand, 
a locality about forty miles from Waikawa. O. Dunlopi possesses the same 
compact stele as our fossils, with leaf-gaps very narrow, and sometimes 
