[PENHALLOwW] NORTH AMERICAN SPECIES OF DADOXYLON 55 
pression of opinion respecting affinities, but permits transfer to such 
group, and at such time as may be justified by more ample knowledge. 
I shall therefore follow this division in the present discussion, and en- 
deavour to harmonise the species diagnoses with it, so far as they are 
based upon structural considerations, which is our only point of view at 
the present moment. 
The genus Dadoxylon, which is now to be discussed as Cordaites, 
has its type in C. Brandlingii as expressed by Brongniart,t who further 
says, “Ces espéces ont, en effet, la plupart des caractéres essentiels du 
bois des Araucaria. C’est-a-dire les ponctuations des fibres lgneuses 
disposées en plusieurs séries alternantes entre elle, et prenant par pres- 
sion la forme d’aréoles hexagonales. Cependant il y a quelques diffé- 
rences assez importantes pour qu’on ne puisse pas aflirmer que ce sont 
de vrais Araucaria, surtout quand on voit que tant de Conifères actuelles 
de genres différentes ont, sous ce rapport, une structure sensiblement la 
méme; et part celle raison, je préfére le nom donné par M. Endlicher, 
en réservant le nom d’Araucarites aux plantes qui, par leurs organes 
de fructification, se rapprocheraient des Araucaria.” 
An examination of various authorities shows some diversity of 
opinion as to the presence of growth rings in these plants. Knowlton 
tells us that these woods are “ characterised by faint lines of demarca- 
tion between the annual rings of growth.”? Güppert, in his diagnosis of 
C. Brandlingii distinctly says* “ligni stratis concentricis obsoletis,’ but 
in describing C. ouangondianum of Dawson, he says “ligni stratis con- 
centricis distinctis,’ a statement borrowed from Dawson. Defining 
the generic characters of Araucarioxylon, Kraus says* “Lignum stratis 
concentricis vel obsoletis.” In looking through the various European 
species of which there are five according to Knowlton,’ not one descrip- 
tion records the occurrence of growth rings. Grand Eury® bases a 
grouping of species upon 
I Growth rings obscure or obsolete, and 
IT Growth rings distinct. 
He thus agrees with Kraus. Into the latter group he brings C. 
Stephanense and C. subrhodeanum, but the absence of figures of the 

* Tab. des gen. de Veg. Foss., 1849, 76. 
* Am. Geol., III., 1889, 106. 
5 Kennt. der conif. Holz. der Pal. Form., 1888, 9, 12. 
* Schimper’s Pal. Veg., II., 1874, 380. 
5 Proc. U. S. Nat. Mus., 1890, XII., 606. 
5 Flor. Carb. de la Loire. 
