150 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Stemherri'ia>. — The fine apociracn of the axis of an erect Sif/iVark 

 already referred to sliows that the pith of these trees was of that 

 transversely laminated character which ^Wos rise to the fossils 

 known as fStcrnhc.vtjiic. Hence we may suppose that some at least 

 of the numerous casts of f^^teniher^ihv found in the Coal- formation 

 have been derived from Sif/illaricr, ; but this can be ascertained only 

 by a careful microscopic examination of the remains of woody mat- 

 tor clinginf^ to the casts. The results of the study of a considerublc 

 number of specimens may be stated as follows : — 



{<() As Prof. Williamson and the writer have shown, some of 

 these Stet'nhcr(/!a-\nt\is belonj? to coniferous trees of the }2;eim3 D(t- 

 (lo.vi/hn. Plate VII. fig. 1 represents a beautifully preserved cylinder 

 of this kind enclosed in the wood of Dadoxi/Ion muteriarum. 



{!>) A few specimens present multiporous tissue, of the typo of 

 Dictijo.ri/Inn, which, according to Williamson, has a Sternberg ia-\)\t\i. 

 Plate VII. fig. 4 affords an instance of this. 



((!) Other examples show a true scalariform tissue, comparable ^vith 

 that of LcphJophJoios or Lepuloilendron, but of finer texture. Corda has 

 shown that jjlants of the type of the former genus (his Lomatophhm) 

 had Sternher<ila-]n\h9,. Some plants of this group are by external cha- 

 racters loosely reckoned bybotanists as ribless Su/nhria;(Chtthrariay, 

 but I believe that they are not related even ordinally to that genus. 

 Plate VII. fig. 5 represents a Sfernherf/in, with tissue partly reticu- 

 lated and partly scalariform. Plate VIII. fig. 7 represents a speci- 

 men with true scalariform tissue. Plate VII. fig. is a scalariform 

 vessel of Lephlophhios drawn to the same scale for comparison. It 

 will be seen that it is of much coarser texture. 



{d). The majority of carboniferous Stn'nhenjm show structures 

 identical with those described above as occurring in erect SI(/!Uitrl(i'. 

 Such Stcrnher<ii<v. and their structures are represented in Plate VII. 

 figs. 2 uid 3, and Plate VIII. figs. 8, 9, 13. Fig. 8 is a reduced 

 section of a large flattened tree, apparently a S!>/i!hria with Stern- 

 herf/ia-])ith (fig. {)), of great beauty, and not dissimilar from those 

 sometimes found in the erect S!,j!ll(n'ia;. The tissue enclosing it was 

 unfortunately imperfectly preserved, but had three rows of pores 

 (fig. 9 a). 



JStrm-tures !n Coal.— The constant association of SifjiUarla with 

 the beds of coal, in the underclays, in the roof-shales, and in the coal 

 Itself IS too well known to require any detailed refenmce ; and the 

 inevitable conclusion that the Su/ilhma^ were tlic principal plants 

 concerned in the accumulation of the mineral fuel of the true coal- 

 measures IS generally accepted by geologists. It would naturally 

 toiiow from this that tissues of Sii/illaria should be more abundant 

 in the coal than those of other plants. Accordingly, as I have 

 shown m my paper on the " Sfninh.roa ir. Coal " ■ 



the 



un vr "^y P^lfr on the "Structures in uoai,' and on .... 



Conditions of Coal-deposition," tissues similar to those above 



described are those which actually occur most abundantly in the 



3ral charcoal of the coal-seams. Thnf nf f>,„ uk„ (i\.L,.. Knvi- 



minen 



• ^ , ,, , coal-seams. That of the liber or fibrous bark 



n^lT "^^^^'^^""^^^"t of all, and that of the woody axis the 

 next m trequency of occurrenee. ^ 



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