HITHERTO KNOWN AS STEKNBEEGIiE. 353 



magnifier brings both them and the lenticular medullary 

 rays distinctly into view. 



The chief question that remains to be considered, is the 

 relation in which the subjects of this memoir stand to the 

 innumerable fragments of coniferous wood, found in the 

 coal measures of every part of the globe. I have already 

 pointed out the very close resemblance, if not identity, 

 between the structures just described, and the Dadoxylon 

 Brandling! (Pinites Brandlingi, Withani), or fossil tree from 

 Wideopen, near Newcastle. Mr. Withara describes all the 

 species of his genus Pinites as characterised by ^* a medul- 

 lary axis of very large size." We have already seen that 

 this constitutes a striking feature of the Sternbergise; 

 indeed, in the case of fig. 10, the large size of the medul- 

 lary cavity, compared with the small thickness of the woody 

 zone, is very remarkable. It is well known, that when once 

 the pith is invested by a zone of woody tissue, it undergoes 

 no further increase of size; so that the diameter of the pith, 

 at least, reveals to us the thickness of the extremity of the 

 growing branch. In the case of fig. 10. the diameter of 

 the pith has not been much less than two inches. We may 

 infer from this, that the habit of the plant has not been that 

 of Pinus larix, or Cedrus Deodara, giving off long slender 

 pendent branches ; but rather that of Araucaria excelsa 

 and imbricata, or Pinus Pallassianus. The branches appear 

 to have been straight, as in the two former examples, and, 

 with thick succulent growing extremities, presenting ex- 

 aggerated examples of what we find in the latter tree. In 

 young plants all these features would be much more marked 

 than in the terminal twigs of larger trees, which may account 

 for the differences between the various specimens. 



It is only by admitting this supposition, at least in the 

 case of the young trees, that the very large size of the pith 

 can be explained. It is well known that, after the medulla 

 becomes invested by a woody zone, it undergoes no further 



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