110 LYCOPODIALES [CH. 



Gymnosperms, Lepidodendron being relegated to the former class 

 because it was supposed to have no power of forming secondary 

 wood, while Sigillaria, characterised by a considerable develop- 

 ment of such tissue, was classed by Brongniart and afterwards 

 by Kenault as a Gymnospcrm. Binney' in 1865 recognised that 

 the two types of stem pass into one another, but it was 

 Williamson^ who provided complete demonstration of the fallacy 

 of the Brongniartian view. 



These two undoubted Pteridophytes agree very closely in 

 anatomical structure and both are now recognised as arborescent 

 genera of Lycopodiaceous plants. In a paper published by 

 Loniax and Weiss in 1905^ a specimen is described from the 

 Coal-Measures of Huddersfield, in which a decorticated stem 

 with the anatomical characters of Binney's Sigillaria vascularis 

 gives off a branch having the anatomical structure which it has 

 been customary to associate with the species Lepidodendron 

 selaginoides, so-called by Sternberg and founded by him on 

 impressions showing well-preserved external characters. 



In 1862 Binney* described petrified specimens of vegetative 

 shoots from the Lower Coal-Measures of Lancashire under the 

 names Sigillaria vascularis and Lepidodendron vasculare. 

 These were afterwards recognised as different states of the 

 same species. A few years after the publication of Binney's 

 paper Carruthers^ identified Binney's species Lepidodendron 

 vasculare with Sternberg's L. selaginoides. The evidence on 

 which this identification rests has not been stated, but many 

 writers have retained this specific designation for the well-defined 

 type of anatomical structure first described by Binney as 

 L. vasculare. The use of the specific name selaginoides is, how- 

 ever, open to objection. The species Lepidodendron selaginoides, 

 as pointed out by Kidston^, is probably identical with the plant 

 which Brongniart had named L. Sternhergii before the institution 

 of Sternberg's species, and we are not in possession of convincing 

 evidence as to the connection of L. Sternhergii (=L. selagi- 

 noides) with specimens possessing the anatomy of Binney's type. 



1 Binney (65) ; see also Binney (72). '^ Williamson (72). 



' Weiss, P. E. and Lomax (05). i Binney (62). 



» Carruthers (69) p. 179. » Kidston (86) A. p. 151. 



