308 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 41. 



the paper in a markedly different manner from what has previously 

 been customary and are considered as representing the polypodi- 

 aceous genus OnycTiiopsis of Yokoyama. 



THE GENUS CLADOPHLEBIS. 



The genus CladopJilebis is essentially a form-genus which is restricted 

 at the present time to include only certain fern remains of Mesozoic 

 age, although this type of frond is practically identical with those of 

 some Paleozoic genera, as for example Pecopteris, and it can also be 

 closely matched by a variety of Tertiary and living ferns. 



CladopJilehis was proposed by Brongniart in 1849 - for those species 

 wliich formed the section Pecopteris neuropteroides in his ''Histoire 

 des vegetaux fossiles" which he regarded as transitional between 

 Pecopteris and Neuropteris. Certain of their characters were men- 

 tioned but no formal diagnosis was attempted. Saporta was per- 

 haps the first to define the genus with precision.^ 



Scliimper in 1874 gives a somewhat amplified diagnosis.^ Later 

 tliis author* abandons CladopJilehis in the behef that the fertUe 

 specimens described by Heer justify the reference of these forms to 

 the modern genus Asplenium. 



The most recent diagnosis is that by Seward, wliich may appro- 

 priately be quoted for the American Cretaceous forms: 



Fronds pinnately divided, pinnee spreading, lobes or pinnules attached by the entire 

 base or slightly 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.^ 



Much difference of opinion has prevailed regarding the unity and 

 the systematic position of the genus, Saporta ** having long ago 

 pointed out that Brongniart's species had nothing in common with 

 those of the Mesozoic and that the Liassic and Oolitic forms, those 

 which the former author was discussing, give evidence of common 

 characters. At the present time there is still lacking evidence from 

 such fructified remains as have been discovered of close relationship 

 between all of the various species of CladopJilehis. Thus Heer dis- 

 covered in the Siberian Jurassic, fragments of the CladopJilehis 

 wJiithyensis type with soral characters which he compared with those 

 of the subgenus Diplazium of Asplenium'' and Schenk has figured 

 fertile pinnules of the same type in the case of the alHed Asplenites 



1 Tableau, p. 25. 



2 Saporta, Pal. France, ser. 2, V6g6taux, Plantes Jurass., vol. 1, 1873, pp. 298, 299. 



3 Schimper, Pal. V6g6t.,vol. 3, 1874, p. 503. 



* Schimper in Zittel's Handbuch der Palaeontologie, Abth. 1, 1890, pp. 99, 100. 

 ' Seward, Wealden Flora, pt. 1, 1894, p. 88. 



6 Saporta, Pal. France, ser. 2, V6g6taux, Plantes Jurass., vol. 4, 1888, p. 357. 

 ' Heer, Flora foss. Arct., vol. 4, 1877, p. 38, pi. 21, figs. 3, 4. 



