Ch. XXIY.] 



FERNS OF CARBONIFEROUS PERIOD. 



469 



of the Carboniferous period are generally 

 without organs of fructification, but in 

 some specimens these are well preserved. 

 In the general absence of such characters, 

 they have been divided into genera distin- 

 guished chiefly by the branching of the 

 fronds, and the way in which the veins of 

 the leaves are disposed. The larger por- 

 tion are supposed to have been of the size 

 of ordinary European ferns, but some were 

 decidedly arborescent, especially the group 

 called Caulopteris by Lindley, and the 

 Psaronius of the upper or newest coal- 

 measures, before alluded to (p. 464). 



All the recent tree-ferns belong to one 

 tribe (Polypodiacece), and to a small num- 

 ber only of genera in that tribe, in which the surface of the trunk is 

 marked with scars, or cicatrices, left after the fall of the fronds. 

 These scars resemble those of Caulopteris (see fig. 513). No less 

 than 250 ferns have already been obtained from the coal-strata; and 

 even if we make some reduction on the ground of varieties which 



Caulopteris primceva, Lindley. 



Fig. 515. 



Living tree-ferns of different genera. (Ad. Brong.) 

 Fig. 514. Tree-fern from Isle of Bourbon. 

 Fig. 515. Cyathea glauea, Mauritius. 

 Fi°r. 516. Tree-fern from Brazil. 



have been mistaken, in the absence of their fructification, for species, 

 still the result is singular, because the whole of Europe affords at 

 present no more than sixty indigenous species. 



Lepidodendron. — About 40 species of fossil plants of the Coal have 



