THE CARBONIFEROUS FLORA. 151 



Wood of Palceozoic Conifers. 



Woody fibres. 



Medullary rays and pith . 



Generic names. 



Geological age. 



No discs. 



One or two series 

 of cells. 



Aporoxylon, Unger. 



Devonian 

 (Erian). 





Complex, or of two 

 or more series of 

 cells. 



Pith Sternbergian. 



f Pitus, Witham. 

 I Palceoxylon, Brongni- 

 ■j art. 

 Pissadendron, End- 

 [ licher. 



Middle and 

 Lower Car- 

 boniferous 

 and Devo- 

 nian. 



Discs in one se- 

 ries contigu- 

 ous, or in sev- 

 eral series 



Simple, or of one 



row of cells. 

 Pith Sternbergian. 



f Araucarites, Goeppert 

 J Dadoxylon, Endlicher. 

 I Araucarioxylon, 

 [ Schimper. 



Upper Carbo- 

 niferous and 

 Permian. 



spirally ar- 

 ranged. 



Pith in spherical 

 chambers. 



Ormoxylon* Dn. 



Devonian. 





Medullary sheath 



scalariform. 

 Medullary rays 



frequent, simple, 



short. 



Dadoxylon (Cordaoxy- 

 lon),t Dn. 



Devonian. 



* Type O. Erianum, Dn., "Report on Canadian Plants," 1871. 

 t Type D. Clarkii, Dn., " Report on Canadian Plants, 11 1882. This may be 

 wood of Cordaites, to which it approaches very closely. 



Family Cordaites, Genus Cordaites, Brongniart. 



Trunks marked by transverse scars of attachment of bases of 

 leaves ; leaves broad, with many parallel veins, and attached by a 

 broad base ; pistillate and staminate catkins of the nature of An- 

 tholithes. Fruit winged or pulpy, of the kind known as Cardio- 

 carpum. Stem with a Sternbergia pith, usually large, surrounded by 

 a ring of pseudo-scalariform vessels, and with a cylinder usually 

 narrow, of woody wedges, with bordered pores in one or more series, 

 and with simple medullary rays. 



From specimens kindly presented to me by Prof. Renault, I 

 have been able to ascertain that the stems of some at least of these 

 plants (Eucordaites) are distinct in structure from all the species of 

 Dadoxylon, above mentioned, except D. Clarkii, of the Erian. They 

 may be regarded as intermediate between those of conifers and 

 cycads, which is indeed the probable position of these remarkable 

 plants. 



Grand Eury has divided the Cordaites into sub-genera, as fol- 

 lows: 



1. Eucordaites. — Leaves spatulate, obovate, elliptical, or lan- 



