SECTION IV., 1900. [ 51] Trans. R. 8. C. 
IIlJ.—Notes on the North American Species of Dadoxylon, with Special 
Reference to Type Material in the Collections of the Peter Red- 
path Museum, McGill College. 
By Proressor D. P. PENHALLOW. 
(Read May 29, 1900.) 
One or two years before his death, the late Sir William Dawson 
placed in my hands a large amount of material representing the various 
species of Dadoxylon collected by him during a period of nearly half a 
century, one typical species from Europe, and several supposed species 
of Cordaioxylon, Tylodendron and Cordaio-Sigillaria, with the request 
that I should revise the whole in the light of our most recent knowledge 
respecting this most interesting group of plants. In the interval, con- 
siderable material has come to hand through Prof. C. 8. Prosser, from 
the Permian and Cretaceous of Kansas, and this has been incorporated 
in the revision, as it was found to.embrace several well known forms of 
Dadoxylon, together with other interesting types. 
Several considerations combined to give weight to the idea that a 
revision was not only desirable but necessary. The genus Dadoxylon 
has been known under a variety of names since Witham’s publication 
in 1833.1. It has been investigated by all the leading palæobotanists 
of Europe and America since that time, and the abundance of material’ 
in America, but more particularly in France, where its remains are to 
be found in great quantity and often most beautifully preserved, has 
led to its being one of the best known genera of fossil plants. So 
ample has been the material, and so perfectly has it been preserved 
in all its parts, that we now have a fairly accurate knowledge of its 
internal structure, as also of its external characteristics including the 
foliage and fruit. Notwithstanding all this however, an examination 
of the literature of the subject discloses a remarkable degree of confu- 
sion as to the plants which properly fall under this genus, their real 
affinities with existing forms, and their limitations with respect to 
geological time. This confusion is not only evident in the type 
material from this part of the world, but it appears in all the writings 
of various authorities and does not disappear from the most recent 



1 The Internal Structure of Vegetable Fossils. 
