126 M. Grand'Eury on Calamites and AsterophyUites. 



outside with ribs, which are internipted and strictly alternate at the 

 articulations, having been in contact with the cortical envelope, 

 which has faithfully preserved its form. 



Outer surface of the bark more feebly fluted and articulated than 

 the inner surface, of which it forms a reflection weakened in pro- 

 portion to the thickness of the bark. Opposite to the articulations 

 branch-scars are present, but not constantly ; and there is no evident 

 trace of the insertion of leaves. 



In place of these there are sometimes, but not always, some 

 small tubercular swellings, which, originating in the interior, 

 only appear distinctly on the outside when the bark is thin ; 

 but as there is at the surface no scar indicated by the absence 

 of the epidermis and by vascular passages, and defined and 

 bounded by a precise line, such as is seen in most stems of the 

 coal-measures, and also on account of their position at the 

 summit of the ribs, they are only the representatives of the 

 rudimentary teeth of an aborted sheath. So that the Cala- 

 mites were destitute both of leaves and sheaths. 



These chief features of organization which the Calamites 

 possess in common with the Equiseta, are associated with 

 characters of subterranean vegetation likewise so capable of 

 identification with those of these same existing plants, that 

 they must be regarded as forming an extinct genus of the 

 family Equisetacese. 



Thus having been able to follow the removal of the 

 floor of a coal-bed in which Calamites Suckowi, Brong., 

 is very abundant in an upright position, I had the good for- 

 tune to see that vertical stems of this species emit at their 

 articulations thin running rhizomes, which, after becoming- 

 elongated to from 0*50 to 1 metre, swell suddenly and rise up 

 as ascending stems — that these, again, in their turn emit fresh 

 definite rhizomes, but only from the elbow which they form 

 in ascending, and so on, producing a succession of stems, 

 which is not without analogy to what we see in EquisetMin 

 variegatum. It is even probable (but this I have not yet as- 

 certained) that the vertical mother stem which gives rise to so 

 many suckers, derives its own origin from a deep-seated rhi- 

 zome. If this were the case, we should have, in these nume- 

 rous groups of rhizomes springing one from the other, as it 

 were the witnesses of an ancient marsh occupied by a species 

 of Calamite, which, just like Equisetum limosum, would have 

 spread over a great space of inundated land. However this 

 may be, the mother stem, the definite rhizomes, and only the 

 base of the ascending stems are furnished with simple or 

 ramose rootlets. 



As regards the other isolated Calamites of the fossil forests 



