CLADOPHLEBIS. 87 



B. Genera which afford no trustworthy evidence as to 

 their affinities with existing families. 



Genus CLADOPHLEBIS, Brongniart. 

 [Tableau, 1849, p. 25.] 



Brongniart, in his " Histoire des vegetaux fossiles," l arranged 

 the numerous species of his genus Pecopteris in several groups, 

 and one of these he called Neuropterides. In a later work 2 this 

 group is reconsidered, with the result that the new generic term 

 Cladophlebis is substituted for those species of Pecopteris included 

 in the Neuropterides. He regards Cladophlebis as a transitional 

 form between Pecopteris and Neuropteris, and points t out its charac- 

 teristics without giving any definite diagnosis. 



Fontaine, in his "Potomac Flora," retains Brongniart's genus, 

 and speaks of the convenience of referring certain sterile fronds 

 to such a genus where venation is the guiding character ; 3 he 

 refers to Saporta as the first to put into a concise definition the 

 distinguishing features of Cladophlebis. The following diagnosis is 

 from Saporta's important work on the Jurassic plants of France 4 : 



" Frons pinnatim divisa, pinnulae ab alterutra discrete vel vix 

 inter se cohaerentes rachi tota basi adnatas aut plus minusve con- 

 tractse subque auriculatae integrae rariusve dentataa ; nervuli e 

 nervo medio orti apicem versus attenuati vel evanidi primum 

 obliqui, dein curvati furcatoque divisi." 



As Saporta remarks, this genus is founded on venation characters 

 and is, therefore, artificial ; but like other similarly constituted 

 genera it is useful for the reception of those ferns the botanical 

 affinities of which are at present unknown. This author includes 

 under Cladophlebis the widely distributed Pecopteris Whitbyensis, 

 Brong., Asplenites Rosserti, Schenk, etc. 



Schimper, 5 in 1874, gave a more exhaustive definition of the 

 same genus, and drew attention to the fact that Saporta's de- 



1 p. 320. 



3 Tableaux, p. 25. 



3 p. 67. 



Pal. FranQ, ser. ii. vol. i. 1873, p. 298. 

 6 Trait, pal. vg. vol. iii. p. 513. 



