o/" Ulodendron to Lepidodendron, &c. 177 



the case with the example from which this sketch was made. 

 This figure illustrates the form of the leaf- scar to which 

 Goppert applied the name of Lepidodendron [Sagenaria) 

 ellipticum *. 



The fissures in the bark do not appear to have ever become 

 filled with a subsequent development of tissue, but to have 

 remained as open gashes, for of the numerous impres- 

 sions of these plants which have come under my notice, 

 in every case these clefts were represented as elevated ridges 

 on the surface of the impression, or SlS. fissures in the bark ; 

 hence they must have been open clefts at the time of minera- 

 lization. Nor do these clefts appear to have been caused by 

 shrinkage or breakage of the bark after the plant was im- 

 bedded in the material which now forms its matrix ; for had 

 it been brought about by any secondary cause, we should 

 expect to find these clefts in the bark of all Lepidodendra^ 

 which we do not. 



But, on the other hand, all Lepidodendroid Ulodendra do 

 not show this peculiar character of the bark becoming split, 

 for I have seen specimens, some of them very large, of a 

 Lepidodendroid Ulodendron from the Scotch Coal-Measures f, 

 in whose bark, in only one case, was there a slight and indi- 

 stinct indication of these vertical clefts. Therefore, although 

 perhaps of specific value, I am not inclined to regard the 

 longitudinal fissuring of the bark as of generic importance. 



From many specimens of these so-called Ulodendra {Ulo- 

 dendron parmatam^ Carr.= Z7. commutatum, Schimper, &c.), 

 some of which I figure (figs. 1-2), portions of the stems had 

 been broken ofi", either from the sides of the fossils or from 

 between the scars ; such pieces could not have been distin- 

 guished from Lepidodendron Veltheimianwn, Sternberg, with 

 which they entirely agree. 



Sigillaria discophora^ Konig, sp. 



I have given on PL IV. fig. 7, a copy of a few leaf-scars 

 of Sigillaria Brardii |, for comparison with those of this and 

 the following species. 



The leaf-scars (a, fig. 7) of Sigillaria Brardii are placed 

 on more or less elevated cushions ((7, fig. 7). These cushions, 

 as in LepidophloioSj are morphologically distinct from the leaf- 

 structure, and belong to the cortical envelope, being portions 

 of it, in fact, only mamilliform protuberances. Superficially 



* Foss. Flora d. Uebergangsgebirges, pi. xliii. fig. 7. 

 t From Eosewell Colliery, Midlothian, and Eonnington Pit, Kilmar- 

 nock, Ayrshire. 



X From Brougniart's Hist. d. v^get. foss, pi. clviii. fig. 4. 



