LEPIDODENDRON. 65 



les Lycopodiacees, et particulierement dans celles clont les feuilles tres nombreuses, sont 

 en rapport avec un nombre proportionnel de faisceaux vasculaires entourant l'axe central. 

 (Voyez la coupe de la tige du Lycopodium verticillatmn, pi. x, fig. 1.) 



" Enfin, la delicatesse du tissu cellulaire qui environne exterieurement ce cylindre 

 vasculaire, et qui le separe du tissu cellulaire plus dense qui forme la zone resistance exte- 

 rieure de la tige, la destruction facile de ce tissu, la position excentrique de l'axe vascu- 

 laire dans l'espece de cavite cylindrique qui resulte de la destruction plus ou moins 

 complete de ce tissu cellulaire, sont des caracteres ou des dispositions accidentelles qu'on 

 recontre tres frequemment sur les tiges seches des Lycopodiacees conservees dans nos 

 herbiers. 



" Ainsi, par la structure interieure de leurs tiges, comme par leur forme exterieure, 

 leur mode de ramification et la disposition de leurs feuilles, les Lepidodendrons s'accordent 

 presque completement avec les Lycopodiacees, et ne seraient autre chose que des Lycopo- 

 diacees arborescentes." 



§ 2. Carruthers. — This author, in his paper published in vol. xiii, pp. 2 to 9, ' Journ. 

 Botany,' says " Lepidodendron was a branching tree of considerable size. It is separated 

 from the other genera of coal plants by the form and arrangements of the leaf-scars upon 

 its stem. More than forty species have been recorded ; but, as the scars present different 

 appearances on different portions of the same plant, no doubt more species have been 

 established than the materials fairly warrant. But that they were numerous in species, 

 and very numerous in individuals, any one who has even cursorily examined a coal-pit, or 

 the fossils in any public museum, must be convinced. They certainly contributed largely 

 to the formation of coal. 



" The researches of Witham, Lindley and Hutton, Brongniart, and Binney have made 

 us acquainted with the stem.'' 



Mr. Carruthers, in a note referring to my papers on Sigillaria vascularis, published in 

 the ' Quarterly Journal of the Geological Society,' and in the ' Phil. Transactions/ speaking 

 of myself, says, " He refers them to the genus Sigillaria, because of their agreement in 

 internal structure with Brongniart's SiffiUaria elegans ; but he cannot separate them by 

 their external markings from Lepidodendron selaginoides, Lindl. and Hutt. ; and, as the 

 only characters by which the two genera are distinguished are derived from the markings 

 of the stem, we must consider Sigillaria vascularis as a true Lepidodendron. I am the 

 more satisfied as to this because I believe no essential difference exists, as has been 

 hitherto maintained, between the stems of Sigillaria and Lepidodendron, or any of the 

 other lepidodendroid plants of the coal period. I cannot enter into this question here, 

 but I shall take an early opportunity of publishing my views and the reasons for main- 

 taining them." 



Mr. Carruthers then goes on to state, " These published observations, together with 

 the examination of some beautiful specimens in the collection of Robert Brown, now in 



