SIGILLARIEAE. 247 



and S, laevigata 1 , these parallel trace-lines may attain a considerable 

 breadth and become almost ovoid, and moving apart from one another 

 may leave a distinct space between them. Such casts were regarded by 

 the older authors as a separate genus and named Syringodendron, Stbg. 

 In these specimens the ribs are usually marked with fine longitudinal 

 striae, which are shown with especial clearness on the mould of the surface, 

 in those places in which the rind of coal remains attached to it and shows 

 us its inner side. How far it is the case that other casts than these occur 

 in Sigillariae, answering to some extent to Bergeria-forms in Lepido- 

 dendrae, is a question which deserves further enquiry. We might conclude 

 from Renault's 2 figure that Sigillaria microstigma, Br. is such a form of 

 preservation belonging to S. tessellata, but since our information about 

 them is scanty, and I have never myself seen any specimens, I must refrain 

 from giving a decision. Since, as will have to be shown later on, Dicty- 

 oxylon-structure of the rind has been observed in some Sigillariae, there can 

 be no doubt but that some of the impressions which answer to this structure 

 (Fig. i B on p. 7, Fig. 22 B on p. 217) will belong to the group which we are 

 considering, though we may not be able to distinguish them from the rest. 



The stems of Sigillariae are accompanied by large numbers of long 

 linear leaves with a keel formed by the strongly projecting median nerve. It 

 is usually assumed that these leaves belong to Sigillariae, and appeal is made 

 to a few discoveries, which though not absolutely proving the connection 

 yet are calculated to render it very probable. In these instances leaves 

 of the above description were found lying apparently in their natural 

 position and nearly parallel with one another upon and close to portions of 

 Sigillaria-stems. But absolute proof is still wanting, for, as far as I know, 

 the attachment of the leaf to the scar of the cushion has never yet been 

 certainly observed. It is remarkable how rare such specimens seem to 

 be, and I can only cite a very few figures from the literature, though 

 Renault 3 states that- portions of Sigillaria elegans, S. rhomboidea and 

 S. Brardii with leaves are preserved in the Paris Museum. The best- 

 known figure is that of Sigillaria lepidodendrifolia in Brongniart 4 ; a similar 

 figure of S. Cortei, which belongs to Rhytidolepis, is given in Geinitz 5 . 

 The figures of S. rimosa, Goldbg and S. aequabilis, Goldbg supplied by 

 Goldenberg 6 are less convincing. From the circumstance that pieces of 

 stem only of Sigillariae have hitherto been found, never any leafy branches 

 such as are so abundant in Lepidodendrae, it maybe concluded that Sigillariae 

 must have had their branch-system very slightly developed, and the con- 

 clusion is supported by the great scarcity of pieces in which branching can 

 be perceived. Wherever it has been observed it is found to be truly 



1 Brongniart (1), vol. i, t. 143. * Renault (2), vol. i, t. 17, f. 3. 3 Renault (2), vol. iii, p. 8. 

 * Brongniart (1), vol. i, t. 161, 1. i. 5 Geinitz (5), t. 6, f. i. 6 Goldenberg (1), t. 6. 



