CHAPTER XII 



THE CORDAITALES 



Poroxyleae ; Pityeae ; Cordaiteae 



I. Poroxyleae 



We now pass on to a group of fossil plants, which 

 occupies a somewhat different position from those which 

 we have just described. The latter were found, on the 

 whole, to combine the characters of the Ferns with those 

 of the great Cycadophytic stock, and might thus be 

 regarded as indicating the probable derivation of the 

 latter from the former. The group next to be con- 

 sidered, that of the Poroxyleae, while having much 

 in common with certain of the Pteridosperms and 

 Cycadofilices, especially with the Lyginodendreae and 

 Calamopityeae, show affinities not so much with the 

 Cycadophyta as with a wholly extinct order of Gymno- 

 sperms, the important Palaeozoic family Cordaiteae. 

 The three families, Poroxyleae, Pityeae, and Cordaiteae, 

 are, in fact, so interrelated that they may best be 

 united under the common class-name Cordaitales. 



The Poroxyleae are represented at present by the 



one genus Poroxylon (of which two or three species are 



500 



