. On the structure and affinities of Sigillaria, Calamites and Calamodendron [microform]. Paleobotany; Paléobotanique. c that I late IX 1 Society. DAWSON—SIGILLARIA, CALAMITE8, AND CALAMODENDRON. 159 idodendra with the SifjillaricB of tho Favulnria-ty])s. On the er hand, as already stated under Sigillaria, the ribbed Sviillarice ,ay be related through Ormo,v>flon and Dadoxylon to tho modem nifcrs, and the Faindainiv may be related to the Cycads. This rc- ioiiship may be expressed as follows:— 1 Cycadacece. Conifero'. Dadoxylon. >r Favularia ? Palieoxylon. Ormoxylon f. Dictyoxylon. 8io] [
. On the structure and affinities of Sigillaria, Calamites and Calamodendron [microform]. Paleobotany; Paléobotanique. c that I late IX 1 Society. DAWSON—SIGILLARIA, CALAMITE8, AND CALAMODENDRON. 159 idodendra with the SifjillaricB of tho Favulnria-ty])s. On the er hand, as already stated under Sigillaria, the ribbed Sviillarice ,ay be related through Ormo,v>flon and Dadoxylon to tho modem nifcrs, and the Faindainiv may be related to the Cycads. This rc- ioiiship may be expressed as follows:— 1 Cycadacece. Conifero'. Dadoxylon. >r Favularia ? Palieoxylon. Ormoxylon f. Dictyoxylon. 8io] [LLARIA. Rhytidolepis. Calamodendron. tv Favularia ? Calamopitus. Clathraria. Eornia. Syringodendron. Calamitcs. ^ Lepidophloios. Equisefacece. (; Lepidodendron*. Lycopodiacece. I do not give this Table with any view to theories of derivation, but merely as an expression of probable affinities among tliese very curious and ancient types of vegetation. I may add here a few words with reference to Sjdunnplyllmn, a genus which some authors unite with Calamites. 'Ino verticillate, Cuneate, veiny leaves of this plant, and its spikes of fructification have long been known ; and in ]8()e5 I was enabled by a specimen in the collection of Sir W. E. Logan to determine the structure of its stem, which contains a slender axis of reticulato-scalariform vessels of the type of those in Tmesipter'n^X. These i)lants obviously had no connexion with Ccdamites or Calamodendron, but constitute a peculiar synthetic type, presenting points of resemblance to Ferns and Marsiliacea). In conclusion, and with reference to my former papers on tho ** Structures in Coal," I would repeat the statement made in those papers, that the tissues of ShjiUarla, as defined in this paper, and of Calamodendron enter more largely than any others into the compo- sition of the mineral charcoal, and other parts retaining structure, of the coal of Nova Scotia ; and I have reason to believe that similar tissues arc a
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