THE CARBONIFEROUS FLORA. 



113 



tlio thin bark and firm wood with which we are familiar 

 in our modern trees, it has a hard external rind, tlien a 

 great thickness of cellular matter with rope-like bands of 

 fibres', constituting an inner bark, while in the centre is 

 a firm, woody axis of comparatively Bmall diameter, and 



Qj;:« 



Fio. 84. — Sigillaria Lonvaynna, Dawson. «, Zones of fruit-sciirt*. b, Laaf- 

 Bcar enlarged, c, i'ruit-scar enlarged. See appended note. 



somewhat intermediate in its structures between that of 

 the Lepidodendra and those of the cycads and the taxine 

 conifers. Thus a great stem, five feet in diameter, may 

 consist principally of cellular and bast fibres with very 

 little true woody matter. The roots of this tree are 



