126 THE GEOLOGICAL HISTORY OF PLANTS. 



of fossil ferns, in which the fructification is for the most 

 part wanting, it is still more so, depending in great part 

 on the form and venation of the divisions of the fronds. 



Fig. 51. — Group of coal-fonnation ferns, a, Odontopteris subcuneata (Bun- 

 bury), b, Neuropteris cor data (Brongniart). c, Alethopteris lonchitica 

 (Brongniart). d, Dictyopteris obliqua (Bunbury). e, Phyllojoteris an- 

 tiqua (Dawson), magnified ; e 1 , Natural size, r, JVeuropteris cyclopte- 

 roides (Dawson). 



Of about eight families into which modern ferns are 

 divided, seven are found in a fossil state, and of these, 

 four at least, the Cyathacece, the OpMoglossece, the Hy- 



