352 SIGILLARIA. 



Thirty-four species of Lepidodendron are enumerated in 

 M. Ad. Brongniart's Catalogue of fossil plants of the coal 

 formation. 



The internal structure of the Lepidodendron has been 

 shown to be intermediate between LycopodiaccEe and Coni- 

 ferae,* and the conclusions which Prof Lindley draws from 

 the intermediate condition of this curious extinct genus of 

 i'ossil plants, are in perfect accordance with the inferences 

 which we have had occasion to derive from analogous con- 

 ditions in extinct genera of fossil animals. " To Botanists, 

 this discovery is of very high interest, as it proves that 

 those systematists are right, who contend for the possibiHty 

 of certain chasms now existing between the gradations of 

 organization, being caused by the extinction of genera, or 

 even of whole orders ; the existence of which was necessary 

 to complete the harmony which it is believed originally ex- 

 isted in the structure of all parts of the Vegetable kingdom. 

 By means of I^epidodendron, a better passage is established 

 from Flowering to Flowerless Plants, than by either Equi- 

 setum or Cycas, or any other known genus." Lindley and 

 Hutton's Fossil Flora, vol. ii. page 43. 



Sigillaina.f 



Besides the above plants of the Coal formation which are 

 connected with existing Families or Genera, there occur 

 many others which can be referred to no known type in the 

 vegetable kingdom. We have seen that the Calamitcs take 

 their place in the existing family of Equisetaceas ; that many 

 fossil Ferns are referable to living genera of this extensive 

 family ; and that Lepidodendra approximate to living Lyco- 



* See annual report of the Yorkshire Phil. Society for 1832. William's 

 Fossil Vegetables, 1833, PJ, 12. 13, and Lindley and Button's Fossil Flora. 

 PI. 98 and 99. 



t PI. 56, Fijrs. ].2. 



