CORDAITALES 



i6g 



resemblance to that of a cycad, except that there is a differentiation 

 of the cortex into two regions, as in so many of the Cycadofilicales. 

 The double leaf trace is very distinct (fig. i8i). In others, there is 

 less pith and cortex and more wood (fig. 182). 



Fig. 1 79. — Cordaites sp: tip of a branch with long leaves and branches bearing stro- 

 bili. Detail from the restoration of an entire tree in the Carboniferous swamp-forest 

 reconstruction in the Field Museum of Natural History at Chicago. 



Cordaites seldom shows any growth-rings, and such rings are rare 

 in Carboniferous woods, indicating that the weather was uniform 



