LEPIDODENDREAE. 2 1 5 



sent small abbreviated lateral branches, the extremities of which were 

 probably occupied by cones of fructification and have dropped off. When 

 Renault takes some of these forms for rhizomes and others for fertile 

 branches, the construction is artificial, and in my judgment rests on very 

 weak foundations and must be rejected. The anatomical reasons which he 

 advances in support of it will have to be discussed further on when we are 

 giving an account of the anatomy of these plants. He imagines too that 

 he has seen the root still attached to a protuberance in one of Binney's 

 specimens 1 ; but this is shown to be a mistake by Williamson 2 , who ex- 

 amined the original in Owens College in Manchester and ascertained that 

 the supposed root was a casual corner of the enveloping sandstone. The 

 latter author moreover long before produced weighty reasons for thinking 

 that Haloniae must have been the fruit-bearing branches of the crown of 

 lepidendroid plants; in a lengthy note on these forms 3 he describes an 

 ordinary and evident branch of Lepidodendron, which after bifurcation 

 retains its character on one branch and assumes that of Halonia on the 

 other. In this case therefore we can no longer speak of our fossil being 

 of the nature of a root, and the idea of a rhizome is excluded, or else the 

 normally constituted sister-branch must also be supposed to belong to the 

 subterranean parts ; we also obtain a point of vantage for determining 

 other more imperfect specimens. This unhappily is all that can be said 

 about Haloniae ; we know neither their leaves nor their fructifications ; 

 neither leaf nor fructification has yet been found in immediate connection 

 with them. 



The structure of the stems and branches of Lepidodendreae is well 

 known to us from the abundant material supplied by the calcareous 

 nodules of the English Coal-measures. Renault has also made us ac- 

 quainted with some small and important stems from Autun, but they are 

 extremely rare in that locality; nor is this surprising, since the entire 

 group sinks into comparative insignificance as early as the upper portion 

 of the Carboniferous formation, to which the beds at Autun belong. On 

 the other hand, we should scarcely know anything of the structure of the 

 leaves, if we did not find them preserved in the cones of the fructifica- 

 tion, of which we shall speak^again presently. We thus are able with 

 some degree of confidence to infer the structure of the foliage-leaves 

 from the character of the fruit-bearing leaves. The structure of the 

 stem, with all the variety of its details, follows everywhere essentially the 

 same fundamental plan. We find a central bundle-strand, from the peri- 

 phery of which the leaf-traces are given off and ascend in a curved line, 

 and a parenchymatous cortical tissue separating into layers of dissimilar 

 character, the outer surface of which, even in thick stems, is bounded by 



1 Renault (2), vol. ii, t. 8, f. i. a Williamson (5). 3 Williamson (1), n, p. 225. 



