420 VEGETATION OF THE CARBONIFEROUS PERIOD 



one genus, ought really to be referred to the other, and that the 

 Sigillaria elegans, whose structure M. Brongniart has ably illustrated, 

 may be amongst them. 



Although the S. elegans here referred to displays no fluting, it is 

 possible that in an older state it might, and that the arrangements of 

 the vascular tissue into separate wedge-shaped bundles, may indicate 

 such a fluting, each ridge answering to one of the wedges ; a conjecture 

 the more probable, from the mass of vessels which supply the leaves, 

 and which lead to scars on the ridges being placed exactly opposite to 

 the wedge-shaped bundles. 



The opinions previously held of the affinities of Sigillaria; are very 

 various, and no less vague, being grounded upon supposed resemblances 

 in their external characters, to certain natural orders of living plants. 

 Thus Artis*, Lindley, and Hutton,t and more recently Corda,} have 

 referred them, with more or less confidence, to Euphorbiacece. 



Schlotheim § to Palmes. 



Von Martius to Cacti. 



Brongniart, originally, [| and 



Sternberg to Ferns. ^[ 



In the earlier years of the study of fossil plants, when their affinities 

 were scarcely known, it was no wonder that observers sought the affini- 

 ties of Sigillarice amongst Dicotyledones ; but now that each successive 

 observation tends to prove that every order of that class,** except 

 Cycadea and Conifer w, were absent from the coal-fields, it is not a little 

 bold to persist, as M. Corda has done, and on very insufficient grounds, 

 in ranking them among Euplwrbiacea. The absence of true woody 

 fibre in any part of these plants, pointed out by Mr. Bunburyf f is con- 

 clusive against Sigillarice being allied to Euphorbiacea? : I may add, 

 that the same objection affects M. Corda's reference of Lepidodendron 

 to Sempervivea?. 



Their reference to Palmar by Schlotheim, is yet more unsatisfac- 

 tory. The central column is of itself a fatal objection, and it is further 

 exceedingly improbable that such numerous Palmce would be petrified 

 without the occurrence of structural specimens. 



The arguments in defence of their being Cacti are nearly what other 

 writers have thought conclusive as to their being Euphorbiacece. 



* Artis, Antediluv. Phytol.,t. 3, 10, 18. 



f Lindley and Hutton, Fossil Flora, I. pp. 94—110; t. 31—36; II. p. 13; III. p. 47, 

 t. 166. 



\ Corda, Flora der Vorwelt, p. 34. § Schlotheim, Essai, p. 23, t. 12. 



|| Brongniart, Mem. Mus. d"Hist. Nat, t. 8, 1. 1, f. 7. 



IT Sternberg, Vers. I. p. 4, t. 38. Vers. II. p. 209, t. 15. 



** See M. Brongniart's excellent remarks on this subject in the " Annates des Sciences 

 Naturelles," 3rd Series, vol. v. p. 52. 



tf Quarterly Journal of Geological Society, vol. ii. p. 120. 



