v; 



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PRB-OARBONIPEROUS PLANTS. 



15 



cumstance which has suggested a name for the genus. The wood of the 

 specimen being carbonized and compressed, unfortunately retains its struc- 

 ture very imperfectly. With some difficulty, however, I was enabled to 

 obtain shreds of the wood showing the tissues represented in the figures, 

 though the general arrangement of these tissues could not be made out 

 any farther than that the cells were arranged in radiating rows, and that 

 there were probably rings of growth. The specimen preserved no cister- 

 nal markings and was evidently decorticated. It must have been about 

 two inches at the least in diameter, independently of the bark. 



The character of the pith suggests affinities with Calamodendron, and 

 shows that the plant must have borne on its nodes verticils of leaves or 

 branchlets, but the structure of the wood is distinct from that of Calamo- 

 dendron, and similar to that of Conifers. It is too dense and thick-walled 

 for that of Sigillaria. The plant therefore stands by itself, and apparently 

 occupies a place between Calamodendron and Dadoxt/lon, but nearer to 

 the latter. 



For comparison I have figured one of the pith-diaphragms of the modem 

 Cecropiapeltata, (Fig. 16.), and a section of the pith oi Dadoxylon Ouan- 

 gondianum, (Fig. 15.) ; also the pith of a Carboniferous Dadoxylon. (Fig. 

 17.) It is evident that the arrangement of the parts in the Erian Dado- 

 xylon has some points of re'jcmblance to that in the present species, while 

 that from the Carboniferous also resembles it, though less closely. Th" 

 present species is thus, in so far as its pith is concerned, a true Stern- 

 bergia, but with very distinct and very thick diaphragms, in the former 

 respect approaching to the pith of Calamodendron, but without its verti- 

 cal striation on the surface of the pith cylinder, a circumstance which 

 indicates an arrangement of the woody wedges more akin to that of 

 Badoxylon or Sigillaria than to that of Calamodendron. 



It is further to be observed that this species agrees with Calamoden- 

 dron in having the diaphragms incomplete or perforated in the middle, so 

 as to be capable of freely admitting sand into the interior. As shown in 

 the figure, however, this was also the case with Dadoxylon Ouangondia- 

 num, and possibly with some of the Sigillarice, into the pith-cavity of 

 which in like manner sand has penetrated, so as to produce casts of the 

 pith in the form of Stembergice, 



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