RELATIONS OP CALAMODENDRON TO CALAMITES. 269 



modified form of aCalaraite ; yet, in it, the parenchymatous 

 constituent cells of these primary rays are replaced by 

 prosenchymatous ones, without disturbance of any of the 

 other Calamitean features of the plant ; the further modi- 

 fications of these prosenchymatous cells merely involve 

 questions of size, and of a slight degree of lignification in 

 Calamodendron, which are surely not features of any ordinal 

 value ! De Bary, speaking of the diff'erence between 

 parenchymatous and prosenchymatous structures, says, 

 " We find cells whose protoplasm and contents are reduced 

 relatively to the strongly thickened and often lignified 

 membrane, and which accordingly, without giving up the 

 properties of typical cells, or their part in the process of 

 assimilation, obviously participate in the mechanical func- 

 tions, i. e. the strengthening of the parts to which they 

 belong ^^ [op. cit. p. 28). In accordance with the clear 

 common sense of the above quotation, I conclude that the 

 substitution of a mixture of parenchymatous and pro- 

 senchymatous elements in the primary medullary rays of 

 Calamodendron for the solely parenchymatous ones con- 

 stituting the same organs in the commoner Calamites, is 

 utterly insufficient to justify the separation of these two 

 plants intoCryptogamic and Gymnospermous groups. My 

 plant, represented in fig. 5, which is obviously an inter- 

 mediate form connecting these two extremes, reduces yet 

 further the value of the small difierences that distinguish 

 them, and at fig. 5,y^", we already find traces of the same 

 combination of parenchymatous and prosenchymatous 

 elements that appears to be characteristic of the primary 

 medullary rays of Calamodendron. 



But one more point yet remains to be dealt with : M. 

 Renault considers that he has obtained clear proof that 

 Calamodendron was a Gymnospermous Phanerogam, inas- 

 much as he believes that he has obtained its male, or anthe- 



