M. De Candolle on Fossil Vegetables. 97 



which exist at present. The proportion of dicotyledonous plants 

 has always continued considerable. It is the characteristic 

 trait of the existing development of the vegetable kingdom, 

 ever since the chalk formation. 



The following Table presents a summary of the vegetation of 

 the four periods. It is formed from the tables of the prodro- 

 mus of M. Brongniart, at the same time placing the genera 

 Stigmaria and Sigillaria amongst the dicotyledons, according to 

 the opinion of Lindley ; and by again reducing the six classes 

 recognised by Brongniart to the four which we admit.* 



With these results before us, we can lecognise with M. 

 Brongniart, that the more perfect vegetables, that is to say, 

 those with the greater number of organs, and those the most 

 distinct, have succeeded to the less perfect ones ; in other words, 

 that the vegetable kingdom appears to have been gradually be- 

 coming more perfect. 



I am aware that the authors of the Fossil Flora of England 

 have rejected this theory,-f- but, as I conceive, on insufficient 

 grounds. The circumstance that they have not found the lower 



• The cycadeae and the coniferse are considered as a group (Gymnospermeae) 

 of dicotyledons, closely allied to the monocotyledons and the aetheogameae. 

 We join the mosses also to the aetheogameae. But these alterations can but 

 in a trifling degree affect M. Brongniart's opinions on the development of 

 the vegetable kingdom. 



f Introduction to VoL I. Lond. 1831. Sciences ct Arts, Juillct 1031. 

 VOL. XVIII. NO. XXXV. JANUAllV 1835. C. 



