CLADOPHLEIils. 141 



Bean's name Pecopteris scarburgensis was applied by him to 

 specimens clearly identical with C. denticulata. 



In Fontaine's Potomac Flora there are several specimens named 

 CladopJilebis falcata ; l these have the same form of frond as 

 C. denticulata^ but there is hardly enough evidence, without 

 having access to the specimens, to warrant the inclusion of 

 the Potomac species among the synonyms of Brongniart's plant. 

 Fontaine also figures some fronds which he names C. denticulate^ 

 but speaks of this species as new, while drawing attention to 

 published figures of Pecopteris denticulata by Heer. z 



A specimen in the British Museum Collection (V. 640) from 

 Steierdorf im Banat, named Pecopteris tchitbiensis, bears a very 

 close resemblance to CladopJilebis denticulate but the pinnules 

 appear to have an entire margin. There are various other fossil 

 fronds which may be compared with CladopJilebis denticulata, e.g. 

 Asplenium distans as figured by Yokoyama 3 from Japan ; but 

 without more trustworthy evidence than a similarity in the form 

 of the sterile pinnie there must always be an element of uncertainty 

 in our comparisons. 4 



The point of most interest as regards the comparison of 

 Cladophlebis denticulata with recent ferns is the evidence afforded 

 by the nature of the fertile pinnules of the fossil species. "We 

 know nothing as to the structure of the sporangia, and our 

 comparisons must rest solely on the form of the fertile segments 

 and the disposition of the sori. It is among the Polypodiaceac that 

 we find the nearest resemblance to the fossil species ; in some species 

 of Aspleniuin, e.g. A. lugubre* also Phegopteris decussata (L.), 6 the 

 fertile pinnules with their thin linear sori parallel to the lateral 

 veins agree closely with those of Cladophlebis denticulata (vide 

 PI. XX. Fig. 35). Raciborski lias suggested the probability of 

 Cladopltlebis denticulata 7 and some other species of the genus being 



1 Fontaine (89), pi. v. figs. 1-6. 



2 Loc. cit. p. 71. 



Yokoyama (89), pi. xiv. fig. 1. 



* Some specimens recently sent to me for identification from South Africa, by 

 Mr. Rogers, of the Geological Commission, Cape Town, appear to be identical 

 with Cladopltlebis denticulata. 



6 Hooker (61), pi. iii. 



8 Christ (97), p. 273. 



1 Raciborski (91), p. 2. 



