Fossil Floras of Cape Colony. 15- 



whole of the base to the pinna-axis, Hke those represented in figs. 16 

 and 17, pi. vi. Among existing species we find it in Onoclea 

 germanica W., AlsopMla juncjJmhiana Mett., Cyathea dealhata Sw.,. 

 Gleichenia glauca Sw., SacUeria cyatheoides Kaulf., Pteris arguta 

 Ait., Todea harhara Moore, also in species of Polypodium, Asplenmm, 

 and other ferns. In previous publications dealing with Mesozoic 

 floras I have drawn attention to the wide geographical range of a 

 similar type of frond during the Ehaetic, Inferior Oolite, and 

 Wealden periods." The form named by Brongniart Pecopteris 

 denticulata and now placed in the genus Cladophlcbis occurs as an 

 element of Jurassic floras in all parts of the world. Fertile pinnae 

 are rarely found, and none that have come under my observation 

 show recognisable sporangia, but attention has elsewhere been 

 drawn to the close resemblance — as regards the form of the sori 

 and their distribution on the lamina — between some English 

 specimens and fertile pinnae of Todea Barbara. i This resemblance 

 is, however, insufficient to serve as a safe guide to affinity, and all 

 that we can say is that it is not improbable that some at least of the 

 fronds of the type represented by Cladophlchis denticulata may be 

 members of the Osmundacese. In a previous work, before the 

 possible relationship to the Osmundacese occurred to me, I included 

 CladopJdehis denticidata as a doubtful member of the Polypodiacese. 

 A fertile specimen of Todea australis (Morr.) from Australia was 

 found sufficiently well preserved to enable Eenault I to examine the 

 sporangia, which he describes as agreeing closely with those of 

 recent Osmundaceae, 



It is obviously impossible to discriminate between the numerous 

 sterile fragments of this form of frond from various geological 

 horizons, ranging from Ehgetic to Lower Cretaceous, and furnished 

 by rocks extending from Greenland to Australia and New Zealand, 

 at least so far as concerns the recognition of distinctive characters 

 that could reasonably be considered of specific rank. A possible 

 method to adopt is to use the term Cladophlebis denticulata (Brongn.) 

 as a comprehensive title for ferns, for the most part of Jurassic age, 

 characterised by bipinnate fronds with linear ultimate segments of 

 the shape and with the venation characters shown in figs. 16, 17, 

 pi. vi. We may in particular cases employ a second name, as 

 denoting a possible variety or form and as an index of locality. 

 In the present instance we may therefore speak of the Herbertsdale 



• Seward (94), p. 95 ; (00), p. 18 ; (00'), p. 184. 



t Seward and Ford (03). J Eenault (83), p. 81, pi. xi. 



