308 CONCLUSION. 



rhoifolia and S. Goeppertiana and on the other with the smaller 

 Wealden type S. ManteUL 



In the case of the ahundant and handsome fern Cladophlebu 

 denticulata we lack convincing evidence of family relationship, hut 

 such indications of soral characters as occur point to a polypodiaceous- 

 affinity. The hipinnate form of frond of this species is practically 

 identical "vvith that of certain Ehsetic ferns, e.g. Cladophlehis 

 Eoesaerti, and with ferns of "Wealden age, e.g. C. Alhertsi. Ferns 

 of the Cladophlehis denticulata type are very ahtmdant in Mesozoic 

 strata, hut in most cases we are unahle to determine their systematic 

 position ; this form of frond is in itself of little or no use as an 

 aid to the recognition of hotanical relationship. 



As I^athorst has stated, it is not improhahle that some of the- 

 Sphenopteroid fronds from the Inferior Oolite rocks may be best 

 compared with species of the recent Polypodiaceous genus Bavallia. 



Passing from these rather doubtful examples of Jurassic 

 Polypodiaceoe, wc may turn to other more satisfactoiy fern species. 

 It is clear that the Matoninese played a prominent part in the 

 vegetation of the Oolitic period ; Matonidium Goepperti and the 

 two species of Laocopteris, L. pohjpodioides and L. Woodwardi, are- 

 fairly abundantly represented by well-preserved fertile specimens. 

 This interesting family, with two surviving species in the Malayan 

 region, occupied an even more prominent position in the Ehsetic 

 than in the Jurassic period. From Ehsetic times, when the family 

 appears to have reached its maximum development, the Matoninese 

 gradually decrease in importance, and at the present day the genus^ 

 Matonia alone remains as a survival from Mesozoic times. 



Bipteridinm. — This family, treated as a subdivision distinct from 

 the PolypodiacesB for reasons already discussed,' appears to have- 

 a geological history similar to that of the Matoninese. Diotyo- 

 fhyllum rugosum, one of the more abundant of Inferior Oolite types, 

 is practically indistinguishable from B. Nilssoni, B. acutilobum, and 

 other Ehsetic species. The genera Camptopteris and Clathropteris 

 afford other Ehsetic examples of the same family, and in the 

 Wealden flora we have the genus Protorhipis, which approaches 

 most closely to the surviving fern Bipteris, another tropical 

 remnant of a Mesozoic family. 



Ante, p. 119. 



