418 BOTANICAL GAZETTE [DECEMBER 
apparently due to disturbance caused by the exit of the large 
leaf traces. 
g. Callus plugs have been demonstrated in the sieve tubes. 
10. A study of the growing point has further shown that the 
‘‘quergestreckte Zellen” and the typical protophloem are of the 
same kind; but it has failed to verify Strasburger’s statement 
that the pericycle and the endodermis arise from a common 
maternal layer. 
‘11. The phloem forms a continuous sheath in the leaf. 
12. The root possesses a a acialee diarch, occasionally 
triarch, vascular axis. 
SUMMARY OF CONCLUSIONS. 
1. The internal endodermis in O. cinnamomea is to be 
regarded as phloeotermal in nature, a fact denied by Strasburger 
in homologous cases. 
2. The medullary and cortical tissues seem to be morpho- 
logically equivalent. 
3. Observations on the anatomy wt the Osmundaceae have 
been confined heretofore to the cosmopolitan O. regalis, and the 
subtropical Todeas. From these observations it was concluded 
by Van Tieghem that this family possessed a type of central 
cylinder anomalous among the vascular cryptogams, a type 
(the medullated monostelic type) peculiar to the phanerogams. 
The writer dissents from this view. It appears to be the case 
that the central cylinder of O. cinnamomea is not medullated 
monostelic, for the medulla is obviously extrastelar. Further, 
it cannot be regarded as gamodesmic on account of the topo- 
graphical distribution of the phloem. The most obvious inter- 
pretation seems to be that it is a degenerate form of the amphi- 
phloic siphonostelic type of central cylinder (polystelic type of 
Van Tieghem). O. cinnamomea, O. regalis, O. Claytoniana form 
a series arranged in order of degeneration of their central 
cylinders, and the same is true of 7. darbara and T. superba. 
The present research was carried on in the Biological Depart- 
ment of Toronto University under the direction of Dr. E. C. 
