922 MR A. C. SEWARD AND MR A. W. HILL ON THE 



The specimen on which the species was founded was presented by the Rev. C. G. V. 

 Vernon Harcourt to Mr Phillips of York, and the latter forwarded it in 1832 to Mr 

 Wttham, who named the fossil Lepidodendron Harcourtii. It was found, as we are 

 told b} T the authors of the Fossil Flora, in the roofstone of a bed of coal worked at 

 Hesley Heath, near Rothbury in Northumberland. The seam is considered by Lindley 

 and Hutton to occupy a position " deep in the Mountain Limestone series." * Witham 

 published several rather crude figures of the internal structure, and compared the 

 anatomy of the stem with that of Lycopodium clavatum ; he agreed with Brongniart's 

 conclusion, based on external characters, that the Lepidodendra should be regarded as 

 Lycopodiaceous plants. Witham's figures and descriptive text are repeated in his 

 important work of 1833. Other drawings are given in the " Fossil Flora," but these are 

 in many respects far from accurate. Adolphe Brongniart t afterwards published 

 a few additional drawings in his Histoire des vegetaux fossiles and in his classic 

 paper on Sigillaria elegans. Under the name Lepidodendron Harcourtii, BinneyJ 

 described some exceedingly fine specimens from the Coal-measures near Dudley, 

 but these belong most probably to the type since named by Williamson § L. 

 fuliginosum. 



Williamson in his latest paper, published in 1895,|| calls attention to the probability 

 that, like Lepidophloios Wilnschianus, L. Harcourtii developed secondary xylem at a 

 comparatively late period of its growth. Bertrand ^ has also expressed similar views as 

 to the late appearance of the secondary wood in the latter species. 



An exceedingly detailed account of Lepidophloios Harcourtii was published in 1891 

 by Prof. Bertrand ## of Lille ; this author draws attention to the close similarity 

 between this species and the plant figured by Corda"M" in 1845 as Lomatofloyos 

 crassicule. 



The chief characteristic features usually associated with L. Harcourtii are (i) the 

 absence or late appearance of secondary wood ; (ii) the nature of the leaf-trace bundles, 

 which consist of a strand of xylem tracheids accompanied by a group of "bast fibres"; 

 (iii) the presence of numerous prominently projecting teeth from the surface of the 

 corona; (iv) the usual absence of the middle cortical tissues. In 1887 Williamson JJ 

 contributed a note to the Royal Society, in which he proposed the name Lepido- 

 dendron fuliginosum for certain specimens incorrectly described as L. Harcourtii ; he 

 mentioned the " duplex structure " of the leaf-trace bundle as a special distinguishing 

 feature of Witham's specific type. Solms-Laubach §§ especially compares L. Harcourtii 

 and Williamson's L. fuliginosum, suggesting for the latter the specific name of 

 Williamsoni \\\\; he refers to the presence of the bast-fibres in L. Harcourtii as one of 



* Lindley and Hutton, loc. cit., p. 45. + Brongniart (37), pis. xx. and xxi. 



X Binney (72), p. 77. § Williamson (87), vide also (93), p. 3. 



|| Ibid. (95), p. 47. IT Bertrand (91), p. 150. ** Ibid. (91). 



tt Corda (45), pi. iii. ++ Williamson (87), p. 7. §§ Solms-Laubach (91), p. 226. 



HI The change of name suggested by Count Solms seems inadvisable, as the older name given to the species by 

 Williamson has been generally recognised. 



