DAWaOX SrOTLLARIA, CALAMTTP-S, AND CALAMOnENDRON. 



r- 



tiii 



r<hc name Cuhmopitus* for a group boliovod to bo intormediuto bo- 

 ♦wceii Culumodeudi'on and truo Calami teH. On still other grounds, 

 i^ornia iind other genera or .subgenera have been separated from Cafa- 

 mltcs proper. Latterly Hehiniper has endeavoured to combine the view 

 of the KquiHotaccouH aflinities and ainiual growth of the .stems of 

 Calamitex with what, at first sight, seems the totally irreconcilable 

 (#0()dy character of tho stem of Ca la modem Iron as described by 

 iCotta, Dawes, and Binney. 



', In all my own publications on this subject, from tho date of my 

 first paj)er on Cahtmites publislied in the Journal of this Societyt, I 

 jjiave lield that Calamites proper aro Eipiisetaceous plants, having 

 the (;xternal characters of their stems preserved, and that in tho lost 

 ?es[)ect they differ from the internal Ciists which belong to Galamo- 

 dendroii. All my subse(iuent observations have served to confirm 

 these conclusions, which I would now iUustratc by tho following 

 considerations. 



1. Tho true Cahtm'des (e.g. CSuckovii, C. cannrpformis, C. Cintii, 

 ike.), when well preserved, present, externally, somewhat fiat smooth 



riated ribs, with distinct nodes, and having, at the upper end of 

 eh rib, a rounded areolc with a central dot or scar, marking tho 

 disarticulation of a leaf, branchlet, or root, or, in some cases, the ex- 

 tremity of one of those radial prolongations of the pith which have 

 been described by Williamson. In one specimen in my i)ossession 

 tht/e is a double set of marks — smaller ones on the node, aj)parcntly 

 belonging to the appendages, and larger marks below tho node, which 

 may represent the radial jjrolongations of the pith (1*1. X. fig. 22). Tho 

 cortical investment is very thin and dense, and presents externally 

 the characters of an epidermis, not showing, as in the case of ^Stern- 

 hetyla or Calamodendron, a coating of woody fibres externally, and 

 therefore cannot be regarded as a mere medullary sheath or, as 

 Scliimper 8U])poscs, the racmb;;ano lining tho hollow interior of the 

 stem. I may remark here, that erect Calamites are sometimes sur- 

 rounded by a calcareous or ferniginous concretionary coating which 

 'must not be confounded with the true sui'face of the stem. 



2. The ordinary Calamites are seen to stand erect, rooted in sitti, 

 and attached together at the bases, or arising from rhizomata. The 

 .stems can be seen to bud from each other ; and the roots can bo 

 traced proceeding from their bases and lower nodes. Figures of erect 

 speciraens were given in my paper on Erect Calamites, and also in 

 that on the South J oggins:^ . Abundant specimens may be obtained 

 in the magnificent petrified Calamite brakes at the last-mentioned 

 locality, and, I venture to say, cannot be studied by any geologist 

 without producing the conviction that the erect cylindrical casts im- 

 bedded in groups in the sandstone must represent the tnio external 

 form of the plant. I have also shown, in the paper above cited, tha4; 

 these erect stems are crushed by lateral pressure, and broken down 



* Preoccupied by Unger for certain Devonian planta. 



t On tho Occurrence of Upright Calamites near Pictou, Nova Scotia, Quart. 

 Journ. Geol. Soc. vol. vii. p. 194. 



J Quart. Journ. Ocol. Soc. vol. vii, p. 194, and vol. x. p. 1. 



