458 



PALEOBOTANY, 



vessels. Outside this, again, is a thick bark, composed mainly 

 of elongated fibres or " bast-tissue," with a thin dense outer 

 rind. 



Fig. 70S.— Lcpidodendron Steriibergii. Carboniferous. 



The genera, or sub-genera, Sagcnaria, Knorria, and Aspid- 

 iaria, are properly to be referred to Lepidodendron. The 

 genus Lepidojyhloios, however, is represented both in De- 

 vonian and Carboniferous rocks by forms which are ge- 

 nerically distinct from Ze2ndodcndron. The genus includes 



