LEPIDODENDRON. 



35 



better acquainted with their true original external character before the plants had been 

 subjected to pressure. Sigillaria, instead of the flat surface and leaf-scars generally seen, 

 had, in large specimens, strong ribs projecting fully an inch beyond the furrows, and 

 divided by narrow furrows. 



§ 3. Internal Structure [Witham and others). — For the first knowledge of the internal 

 structure of the stem of Le]3idodendron we are indebted to Mr. Witham/ Messrs. tiindley 

 and Hutton," and M. Adolphe Brongniart.^ The branches dichotomised with great 

 regularity, and at their extremities produced the cone so well known as Lepidostrobus. 

 This latter fact had, for the most part, been inferred from the number of specimens of 

 Lepidostrobi being found around and about the stems of Lepidodendron, rather than by 

 any actual proofs of the cone being found actually attached to the stem itself. 



§ 4. Internal Structure and Cones [Hooker). — Dr. Hooker, to whom we are indebted 

 for most valuable information as to the nature of Lepidodendron, in his memoir previously 

 quoted gives, at page 451, the following descriptions : 



"1. Lepidodendron elegans. Cone slender, three quarters of an inch in diameter, 

 four to ten inches long ; sporangia eight in a whorl. 



" 2. Lepidodendron Harcourtii ? Cone broad, one and a half inch in diameter ; 

 sporangia about sixteen in a whorl. 



" If, now, these cones be examined with reference to the known contemporaneous 

 fossils which accompany them, it will appear impossible to deny their having been the 

 reproductive organs of Lepidodendron, not only from their association with the fragments of 

 that genus, because the arrangement of the tissue in the axis of the cone entirely accords 

 with that of the stem of Lejndodendrony just as we find in modern cones of Lycopo- 

 diacea and Coniferce that the axis is a continuation of the branch which bears leaves, 

 modified into organs adapted to support and protect the parts of fructification.'' 



Now, although the author was quite right in his conclusion that Lepidostrobus was the 

 fruit of Lepidodendron, in the beautiful plates which accompany his memoir there is no good 

 transverse section given to prove thefact; and some writers, especially Mr. Carruthers, consider 

 the evidence of the connection between a Lepidodendron and its own Lepjidostrobus to be 

 consequently of a very unsatisfactory nature.^ Of course the occurrence of the cones in 

 the insides of stems is by no means satisfactory, as any one knows who has examined the 

 stems of Sigillaria, wherein are found plenty of Ferns, which certainly would not be admitted 



' ' On the Internal Structure of Fossil Vegetables found in the Carboniferous and Oolitic Deposits of 

 Great Britain,' by II. T. Witham, Edinburgh, 1833. 

 - ' Fossil Flora of Great Britain,' vol. ii, p. 46. 

 ^ 'Hist. Veget. foss.,' vol. ii, pp. 37 and following, plates x and xi. 



^ "On an Undescribed Cone from the Carboniferous Beds of Airdrie, Lanarkshire," by W. Carruthers, 

 F.L.S. ; 'Geol. Mag.,' vol. ii (No. xvi), p. 437. 



