210 LYCOPODIALES [CH. 



The surface of the specimens shows crowded rhomboidal scars 

 surrounded in some cases by a very narrow border or 

 cushion ; the general appearance is, as Kidston maintains, like 

 that of Sigillaria Brardi in which the leaf-scars are contiguous 

 (e.g. fig. 203, upper part). None of the leaf-scars exhibit 

 the three characteristic features, the leaf-trace and parichnos 

 scars, but only one small scar appears on each leaf-base area. 

 In a more recent paper Kidston figures a small piece of a 

 stem from Kilmarnock, which he identifies as Sigillaria dis- 

 cophora, showing the three characteristic scars on the leaf- 

 base area. There is no doubt as to the Sigillarian nature of this 

 specimen, but it is not clear if the piece figured is part of a 

 Ulodendron shoot ^. 



Prof. Zeiller^ retains the older name Ulodendron minus Lind. 

 and Hutt. in place of Konig's specific designation and dissents 

 from Kidston's identification of Ulodendron minus and U. majus 

 of Lindley and Hutton as one species ; he is also inclined to 

 refer these Ulodendron axes to Lepidodendron. In spite of the 

 superficial resemblance to Sigillaria of the specimens described 

 by Kidston, and which I have had an opportunity of examining, 

 I venture to regard their reference to that genus as by no 

 means definitely established. We must recognise the difficulty 

 in certain cases of drawing any satisfactory distinction between 

 Sigillaria and Lepidodendron based on external features, and 

 while giving due weight to the conclusions of so experienced a 

 palaeobotanist as my friend Dr Kidston, I venture to think we 

 are not in a position to state with confidence that Sigillaria 

 possessed Ulodendron shoots. 



ii. Leaves. 



The leaves of Sigillaria agree closely with those of Lepi- 

 dodendron; they are either acicular (fig. 200, D) like Pine 

 needles or broader and flatter like the leaves of Podo- 

 carpus. Their attachment to comparatively thick branches' 



1 Kidston (892) p. 61 ; PI. vi. fig. 1. 



2 Zeiller (88) A. p. 483, Pis. Lxxin. lxxiv. 3 Zeiller (06) PI. xlii. 



