76 



BRITISH EOCENE FLORA. 



This description applies equally to the Miill form, about fifteen specimens of which 

 I have examined. They, except fig. 5, were all found by Mr. Koch in 1880, and include 

 facsimiles of the forms of lobation and venation seen in the existing species, while their 

 texture and preservation led me to anticipate a living representative with mem- 

 branaceous fronds and fine, distinct black veins. The fertile fronds, as in nearly all 

 Perns in which these are separate and unexpanded, are unknown fossil, and we have here 

 the only pretext which can possibly be held to justify the continued separation of the 

 Tertiary forms of at least the Clirysodium, Osimmda and Onoclea just described, from the 

 surviving species. 



The distribution of the Bournemouth Gleichenia is at present the most restricted of 

 any fossil Fern that has been met with at all plentifully, for it is absolutely confined to the 

 small local patch near which it grew. Its peculiar climbing growth has been sufficiently 

 described and is no longer met with in living Gleichenias. The Anemia, a graceful and 

 well-marked Fern, seems a survival from the Cretaceous period, since extinct, and to have 

 been descended from a northern pre-eocene group. From the plants with which it is 

 associated at Bournemouth, it appears to have been epiphytal, occupying the same 

 position that the not very dissimilar Davallia does in the moist and luxuriant forests of 

 Madeira at the present day. The Lygodiiim, associated with it at Bournemouth, 

 undoubtedly occupied similar stations. It possessed larger and more variable fronds 

 than the American species most resembling it, and which seems to have become but 

 recently acclimatised to the temperature it now supports in the United States, since it 

 would probably otherwise have been found in some of the more northern Eocene floras. 

 The much smaller size of the fronds in the Swiss Miocene show, perhaps, that a change 

 was even then in progress. The Heivardia, a remarkable form of Adiantum with 

 anastomosing venation, probably possessed habits analogous to those of A. reniforme at 

 present. It, like the Anemia, Lygodiim, Marattia, Phymatodes, and several others, can 

 only be looked upon as extinct species, whose resemblance to tropical American, rather 

 than to any other living species, is a fact that acquires significance through the accumu- 

 lation of instances. 



The only Ferns among them resembling existing European species are Pteris eoccenica, 

 P. Poumensis, and Adiantum apalojjhyllim, but the wide range and the number of species 

 contained in the corresponding types at the present day, render it difficult with our material 

 to identify them more definitely with one than another. The Goniopteris section of the 

 Polypodies, of which three species were described, would perhaps be more correctly repre- 

 sented by two, through the union of G. 2Jra-cuspidata and G. stiriaca. The latter had 

 apparently a northern range, though the remains are not very distinct, and from the 

 variation among them it is possible that several species or genera are included under the 

 same name. The British species was able to thoroughly establish itself at Bovey-Tracey, 

 but not, so far as we yet know, elsewhere in either England or France, though it 

 abounded in Switzerland. G. Bimhurii is easy to identify notwithstanding that the vena- 



