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EOCENE FERNS. 65 



of the upper surfaces of the fronds above the sori of P. geminatum and the other species 

 named, shows that this peculiarity is shared by them in an identical manner. In texture 

 and every other comparable character they are the same. Only slight traces of this group 

 have been met with elsewhere. The form named Glossoclilamys appears also, from more 

 perfect specimens (Pi. XII, figs. 8, 8 a), to be AcrosticJmm, allied perhaps to A. Pres- 

 lianum, Hk,, A. variabile, Hk., and A. nicotiancefol'mm, Swz. 



10. Chrysodium Lanz^eanum, Visiani. (Page 26.) 



The species is one of the most distinctly characterised of all the Eocene Ferns, and 

 so closely resembles C. aureum as to be indistinguishable from it, except that in luxuriant 

 fronds from the Middle Eocene the pinnae are sometimes more decurrent than has been 

 observed in the living species. It has been found abundantly in the Lower, Middle, and 

 Upper Eocenes, or Oligocene in England, and in similar beds in France and Austria. 

 The existing species is spread over almost the whole coasts of the Tropical and sub- 

 Tropical World and prefers sea air. The pinnules seem to decrease in size from Lower 

 to Upper Eocene, but no good specific distinction is apparent.^ 



11. OsMUNDA Heerii, Gaudiii. (Page 53.) 



This species may be said to be almost indistinguishable from 0. regalis. It has not 

 been found fossil in England unless Osmundites Boivkeri, from the Thanet Sands, be its 

 stem. It appears as early as in the supposed Neocomian Komeschichten of Greenland, as 

 0. petiolata, and may probably be united with Ferns of even older rocks. It next 

 occurs in the supposed Upper Cretaceous of Atanekerdluk, as 0. Heerii and 0. Ober- 

 giana.^ It has also been found in the Eocene Lignitic of Am-erica, the Aquitanian of 

 Switzerland, the supposed Miocene of Manchuria and Greenland (?), and the Quartenary 

 of Madeira. 



1 The late M. Watelet's collection from the Gres du Soissonnais having come into my possession, 

 I am able to state that Lygodium crassicostatum, Wat., and L. capillare, Wat., figured, Plate xiii, 

 ' Plantes foss. du Bassin de Paris,' appear to be merely fragments of C. Lanzaanuni. The indistinctness of 

 the specimens, which are in a coarsely-grained matrix, and the possession of a dried frond of a Lygodium 

 with anastomosing venation and somewhat similar outline, doubtless led to their otherwise unaccountable 

 reference to that genus. 



" There seems a possibility, from the figures and descriptions published by Heer, that Asplenium 

 Boreyana, A. Nordstr(xmi, and Pecopteris Pfaffiana, may be but a smaller variety of it, since the only 

 supposed marks of sori mentioned among any of the latter were found on a single small specimen, and 

 stated to be very indistinct. 



