468 



CARBONIFEROUS FLORA. 



[Ch. XXIY 



stand the true nature of Stigmaria ; and in order to explain what is 

 now known of this plant, and of others which have contributed by 

 their decay to produce coal, it will be necessary to offer a brief pre- 

 liminary sketch of the whole carboniferous flora — an assemblage of 

 fossil plants with which we are better acquainted than with any other 

 which flourished antecedently to the Tertiary epoch. It should also 

 be marked that Goppert has ascertained that the remains of every 

 family of plants scattered through the coal-measures are sometimes 

 met with in the pure coal itself — a fact which adds greatly to the 

 geological interest attached to this flora. 



Ferns. — The number of species of carboniferous plants hitherto 

 described amounts, .according to M. Ad. Brongniart, to about 500. 

 These may perhaps be a fragment only of the entire flora, but they 

 are enough to show that the state of the vegetable world was then 

 extremely different from that now prevailing. We are struck at the 

 first glance with the similarity of many of the ferns to those now 

 living, and the dissimilarity of almost all the other fossils except the 

 Coniferse. Among the ferns, as in - the case of Pecopteris for example 

 (fig. 511), it is not always easy to decide whether they should be re- 



Fig. 511. 



Fig. 512. 



Pecopteris lonchitica. 

 (Foss. Flo., 153.) 



a. spnmopierts crenata. 

 o. Part of the same, magnified. 

 (Foss. Flo., 101.) 



ferred to different genera from those established for the classification 

 of living species ; whereas, in regard to most of the other contempo- 

 rary tribes, with the exception of the fir tribe, it is often difficult to 

 guess the family, or even the class, to which they belong. The ferns 



