LINNB<VN SOCIETY OF LONDON. 19 



3. In the third Period the Fenis, and still more tlie singular 



family of Cycads, \vere dominant to such a degree that 

 the species of the latter family were already more numerous 

 than those now existing, and' this little group, which only 

 forms the 2000th part of living plants, constituted half the 

 flora of that epoch. [Mesozoic] 



4. Plants much less different from those which still exist, — the 



same families and most often the same genera which still 

 inhabit our climates. In spite of their analogy with recent 

 vegetation, these fossils are no less worthy of our attention, 

 for they may solve questions of great interest for the history 

 of the "latest changes in the surface of the globe : they can 

 decide whether plants, like animals, have experienced great 

 specific changes during the latest revolutions to which our 

 globe has been exposed. [Tertiary.] 



We must not suppose from these words that Brongniart was an 

 evolutionist, for, as Saporta says, he always opposed evolution, 

 the doctrine to which his own discoveries lent the strongest 

 support. At the same time the whole tone of Brongniart's 

 prospectus and introduction to his great book is thoroughly 

 modern and enlightened. 



His classification of plants was a singularly natural one, and 

 indeed scarcely differs in its main divisions from our modern 

 system. He has six great classes : — 



I. Agames: Algae, Fungi, Lichens [=Thallophyta]. 

 II. Cryptogames celluleuses: Ilepatics and Mosses [=Bryo- 

 phyta]. 



III. Cryptogames vasculaires [ = Pteridophyta, but with the 



addition of Characete]. 



IV. Phanerogames gymnospermes. 



V. Phauerogames angiospermes monocotyledones. 

 VI. Phauerogames angiospermes dicotyle'dones. 



There is little room for criticism here. The name Agames, 

 which is used for Thallophytes, shows that little was known at 

 that time of sexual reproduction in these plants, though the 

 discoveries of Vaucher had already given the clue. Brongniart 

 is quite sound on the Mosses, which lie rightly says have nothing 

 in common with the "Agames" beyond the absence of vessels. 

 It must be remembered that at that time, owing to the splendid 

 early work of Hedwig, the Mosses were much better understood ' 

 as regards their reproduction than the Vascular Cryptogams. 



Brongniart thought that the stems of the Vascular Cryptogams 

 had some analogy in structure with those of Monocotyledons. 

 He says that their organs of reproduction appear always to 

 consist o£ two sexes ; in those days, long before the advent of 

 Suminski and Hofmeister, there must have been a certain amount 

 of luck in arriving at this true conclusion. He explains further 



c 2 



