530 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vou. VIII. 
Obviously the protostelic fossils do not enter into the question. The 
siphonostelic forms later than the Cretaceous Osmundites Skidegatensis 
may also be passed over, for, to say the least, they do not lend strength 
to the arguments of Kidston and Gwynne-Vaughan, and Bower, that is, 
if their standards of interpretation of phylogenetic stages be rigidly 
extended to stratigraphical sequences. This leaves for consideration 
Osmundites Dunlopi, Osmundites Grbbeana, and Chelepteris gracilis. 
The sole material of Osmundites Dunlop is a single specimen of a 
portion of the stem three cms. long, ‘“‘that had suffered acertain amount 
of decay and attrition before it finally became embedded in the rock.” 
‘‘Most of the leaf-traces if not all, depart without in any way interrupting 
the continuity of the xylem ring so that the medullary rays characteristic 
of the Osmundaceous stele in general are almost completely absent.” 
What the xylem surrounded we do not know, for there is in this region 
‘‘no trace of cell-structure.’’ Scale leaves were found, which were believed 
to be due initially to certain adverse external conditions. 
Chelepterts gracilis was studied from a specimen in a fair state of 
preservation, but lacking the extreme periphery of the stem, and from 
which ‘‘the central tissues have unfortunately disappeared.’’ Moreover 
there seems to be some uncertainty as to the relationship borne by Chelep- 
teris to the Osmundacee. 
Osmundites Gibbeana is also based on a single specimen of a part of 
the stem about two cms. long. ‘‘The inner cortex and peripheral tissues 
of the stele were greatly decayed before fossilization;”” there were medul- 
lary rays, but the tissue that composed them ‘‘has entirely disappeared.” 
Presumably the same fate befell the tissues within the xylem. 
Interesting as are these fossils, the soft tissues were not preserved, 
so that it is impossible to say what the xylem enclosed. Nor do they throw 
a ray of light on the origin of the pith—the crucial point, for without any 
question as to affinities, Grammatopteris, etc., might very well be re- 
garded in the Osmundacee as is Lygodium in the Schizeacee, and the 
others, marked as they are by no medullary rays or very narrow ones, as 
reduced forms. In fact Osmundites Dunlopi possessed scale leaves, and 
was admittedly reduced, and the critical features (absence of medullary 
rays, Or very narrow ones) of Osmundites Dunlopi, O. Gibbeana, and 
Chelepteris gracilis Were just such as may be induced in Osmunda cinna- 
momea by subjecting it to adverse conditions. 
It is significant that the Osmundacee can be traced back so far, 
and Kidston and Gwynne-Vaughan have made an important contribution 
