THE CARUOXIFKIiOUS FLORA. 



109 



and narrow furrows and utKluliitcd in a rcmarkahln mannfr oven 

 when lilt' HtciiiHure Jliitt«'iH'<l. Tliis iniil illation is, liowcvcr. iMi'liapsim 

 itifJication of vcrliuil pn-ssurti while the plant w»ih living, a-^ it secfrns 

 to huvo hwl an unii.siially thin and fceblo rortical layer, and the im- 

 dulation.s are ap|mreiitly Ix-.st developed in the lowtrr f)art of the stem. 

 At the nodes the ril)s are often narrowed and ^utliered to^'eiher, 

 cspocially in the vieinity of the roiinde<| radiating niark.s whieli ap- 

 jiear to indi(.'at(! the jjointH of inwirtion of the branches. At th(! top 

 of each rih we have the usual rounded aroole, probably tnarkin;; the 

 insertion of a primary branchlet. 



The braniln-s liave slender ribs and distal t nodes, from whieh 

 Hpriiiff secondary branchlets in whorls, these bearing in turn small 

 whorls of acMcular lealhits nnieh curvcid upward, and which are ap- 

 parently round in entss section aii<l delicately striate. 'J'hey aro 

 much shorter than tlii; leav(;s of ('(iltunili-» Suckovii, iind aro less 

 dense and less curved than those of C. nodosKs, which I iKrlievc lobe 

 the two moHi closely ullied sjjocies. 



Les(piercux notices this s|)eci»;s asr-haractoristic of the lower part 

 of the Carboniferous in Arkansas. 



It will be observed that I regard the striated and ribbed stems not 

 as internal axes, but as representing the outer surface of the [ilants. 

 This was certainly the (tase with the f)resent sjiecies and with C. 

 iSur/iovii and ( '. hoi/ohuh. Other speci(!s, and espe<'ially thos<! which 

 belonged to ("alamodendron, no d(jubt had a smooth or irregularly 

 wrinkltMl external bark; but this gives no good ground for the man- 

 ner in which some writers on this subje(;t cfti.'found ('alainites with 

 Calamodendra, and both with Asterophyllit(!S and Spheiiophylliim. 

 With this no one who has studi(;d thes<' plants, r(M)ted in their native 

 soils, and with their appendages still attached, can for u moment 

 sympathise. One of the earliest geological studies of the writer was 

 a bed of these erect Calamites, which h(! showed to Sir ('. Lyell in 

 1H44, and described in the " I'roeecidings of th(i (ieologi(;al Socictty" 

 in 1851, illustrating the habit of growth as actually seen well ex- 

 posed in a sandstone cliff. Abundant opportunities (jf verifying 

 the conclusions formed at that tiimt have since occurred, the results 

 of wlii<'h have b(;en summed up in the figures in Acadian (jc<jlr>gy, 

 which, though they have Ixien treated by some Ijotanists as merely 

 restorations, are in reality rej)resetilations of facts a<;tiially observed. 



On these subjects, without entering into details, and referring 

 for these to the elaliorate discussions of Schimpcr, Williamson, and 

 McXab, and to my paper on the subject, " Journal of the Geological 

 Society," vol. xxvii, p. 54, I may remark : 



