256 STUDIES IN FOSSIL BOTANY 



Stigmaria, differing in certain respects from the 

 specimens grouped under Stigmaria ficoides. 



Xenophyton radiculosum, a fossil described by Mr. 

 T. Hick in 1891, 1 has been shown by Professor F. E. 

 Weiss, in agreement with a suggestion of Williamson's, 

 to be a Stigmaria. The pith and the whole of the cortex 

 are preserved, giving the specimen a very different char- 

 acter from that of the ordinary S. ficoides. The wood, 



Fig. 105. — Stigmaria ficoides. Transverse section of rootlet, showing dichotomy. The 

 outer cortex, differentiated into two zones, is still continuous, while the inner cortex 

 of the two branches has completely divided, v.b., the two monarch vascular bundles. 

 X 23. S. Coll. 172. (G. T. G.) 



which is little developed, appears to be wholly centri- 

 fugal, as in that species. The rootlet-bundles take a 

 steeply acropetal course, like leaf-traces, and secondary 

 parenchyma is formed about them in passing through 

 the middle cortex, which has a similar structure to 

 that of Lepidophloios fuliginosus, the plant to which 

 Professor Weiss believes this Stigmaria to have belonged. 

 Within the periderm there are strands of secretory cells, 

 as in so many Lepidodendroid stems. It was in a 



1 Hick, "On a New Fossil Plant from the Lower Coal-measures," 

 Journal Linnean Society, vol. xxix. 1892. 



