88 CLALOPHLEBIS. 



scription agrees with that previously given hy himself of the group 

 of Jurassic ferns of the type Alethopteris Whitbyemis. Fontaine 

 slightly modifies Schimper's definition, and suggests that with the 

 addition of " midnerve strong at base, and towards the summit 

 dissolving into branches," we have a well-defined group of ferns 

 " strongly characteristic of the Jurassic, and which is fully as much 

 entitled to be called a genus as is Sphenopteris or Pecopteris" 1 



In his more recent contributions to the French Jurassic flora, 

 Saporta continues to make use of Cladophlebis as a genus, and 

 adds that the Carboniferous species originally included by Brong- 

 niart in his group Pecopteris Neuropteridis, for which the term 

 Cladophlebis was subsequently proposed, have nothing in common 

 with the Liassic and Oolitic species of that genus. The Jurassic 

 species, he observes, give evidence of common characters which 

 point to a well-marked type \_Cladophlebis tennis (Brong.), C. Whit- 

 byensis (Brong.), C. ligata (Phill.), C. Haiburnensis (Lindl.), C. 

 lobifolia (Lindl.), and several others, "se ressemblent entre eux 

 et temoignent d'une parente tenant au moins, a leur physionomie 

 commune "]. 2 Granting the existence of these common characters 

 there is still, as Saporta, indeed, recognizes, no evidence from such 

 traces of fructification as occur of any true relationship (" con- 

 generes ") ; indeed, the fructification, so far as it is known at 

 all, points to the inclusion of ferns of different families under 

 this single generic name. 



We may adopt Schimper's definition, with certain modifications : 3 



Fronds pinnately divided, pinna3 spreading, lobes or pinnules 

 attached by the entire base or slightly contracted towards the place 

 of attachment, rarely somewhat auriculate, acuminate, or obtuse, 

 occasionally dentate, especially at the apex, not rarely subfalcately 

 curved upwards, midrib strong at base, and towards the summit 

 dissolving into branches, secondary veins given off at a more or 

 less acute angle, dichotomous a little above the base, and repeatedly 

 dichotomous. 



It should be noted with reference to the present genus that 

 Heer 4 has included under Asplenium those Jurassic ferns which 



1 Potomac Flora, p. 67. 



* Pal. FraiKj. ser. ii. vol. iv. p. 357. 

 8 Trait, pal. veg. vol. iii. p. 513. 



* Fl. foss. Arct. vol. iv. 1877, p. 38. 



