440 



THE CARBONIFEROUS SYSTEM. 



described by Goeppert as Araucarites carhonarius is probably also 

 Sigillarian. 



2. Calamodendron or Calamitea. — These plants are much less known 

 than the proper Sigillarias, and it is perhaps doubtful if they should 

 not form a separate family. In the meantime I place them here, 

 simply because they seem to approach more nearly to SigillaricB than 

 any other plants in their structure. They were of less massive growth 

 than Sigillarice, being rarely more than a few inches in diameter ; they 

 had stems fluted lengthwise like Sigillarla, but more distinctly 

 divided into nodes or joints by the scars of branches which were borne 

 in whorls, and carried their narrow, slender leaves. In their habit of 



Fig. 162. — Calamodendron. 



(a, b) Casts of axis in sandstone, witli woody envelope, reduced. 

 («, d) Woody tissue, highly magnified. 



growth they thus resembled the pine tribe, and they seem to have had 

 a larger amount of true wood in their stems than was the case with 

 Sigillaria. This cylinder of wood contained a thick pith, which was 

 constricted at intervals into joints, and had also a longitudinal striation 

 on the outside ; and as this pith from its ready decay admitted sand 

 into the interior of the stem, while the wood was entire or in process of 

 conversion into coal, we often have a stem of Calamodendron repre- 

 sented merely by a cast of the pith in stone. In this case the pith 

 cylinder may be easily mistaken for a plant of the genus Calamites, 

 which, as we shall immediately find, was quite a different thing. I 



