25° 



STUDIES IN FOSSIL BOTANY 



the origin of the latter could not have been endogenous. 

 Probably the rootlets were formed excessively near the 

 apex of the parent organ. 



We have now to describe the characteristic structure 

 of the fre'e rootlet, but may first point out how the 

 anatomy of its base exactly accounts for the configura- 

 tion of the scars on the ordinary Stigmarian surface 



Fig. ioi. — Stigmariaficoides. Transverse section of rootlet, in usual state of preservation. 

 o.c, outer cortex ; i.c, inner cortex ; x, xylem. x 16. S. Coll. rr3. (G. T. G.) 



(compare Fig. 97 with Fig. 101). The outer cortex 

 answers to the raised external rim of the scar ; the 

 lacunar middle zone to its depressed surface ; the inner 

 cortex to the internal circle of the scar ; and the 

 vascular strand itself to the minute central point seen in 

 the latter, when especially well preserved. 



The rootlets of Stigmariaficoid.es are absolutely the 

 commonest specimens among the petrified material of 



