32 BRITISH EOCENE FLORA. 



Saporta objects to the reference of this fossil to a Fern, as he considers the venation to 

 be quite unlike that of any Fern, and to belong to a type common among dicotyledons. 

 Heer also states that, in his opinion, "it is not a Fern, but a leaf of a Dicotyledon." It 

 is found associated with Podoloma. 



(c) Pteridecs. 



Pteris eoc^nica, Etf. and Gard. Plate IV, figs. 4 — (5. 



P.fronde pinnata, jnnnis rhacJd anc/ulo peracuto insertis, sessilibus valde elongatis, 

 lanceolato-linearibus, acuminatis, basi obliquis, margine tenuissime serrulatis ; nervatione 

 Nenropteridis acrostichacece, nervo primario prominente, redo^ apicem versus sensim 

 attenuato ; nervis secundariis sub anr/ulis 40 — 50° orientibus, ] ' 5 millim. inter se distantibus^ 

 bi- vel trifurcatis, rarissime simjdicibus, ramis inter se parallelis, cum nervo primario 

 anyulum, subrectum formantibus. 



Middle Bagshot, Bournemouth, 



This species is characterised by its long, narrrow pinnae, which quit the rachis at 

 angles of about 25°. Towards the apex of the frond they are sometimes confluent, 

 decurrent below on the rachis, as in PI. IV, figs. 4 and 5, and apparently petiolated 

 towards the base. The terminal pinna is the largest. The margins of the pinnae are 

 sinuous or alternately lobed, and very finely toothed. The midrib is prominent and 

 elongated. The secondary veins are numerous and crowded, spring at acute angles, 

 curve outwards to the margin, and terminate in the teeth, the majority of them being 

 once, some twice forked, and a very few undivided,. The venation is of the type of 

 Neuropteris acrostichacea, which is not uncommon in recent and fossil species of Pteris. 



P. eocanica resembles very closely a number of living species of Pteris, as P. crenata, 

 P. cretica, &c. It also resembles the Aquitanian species, P. pennaformis, Heer,^ but 

 may be distinguished by the secondary veins, which are less crowded and more generally 

 forked, and by the margin, which is lobed and toothed in a much more pronounced 

 manner. It even more closely resembles P. ParscUugiana, linger, and P. Gaudini, Heer, 

 but differs from the former in the much more acute angle at which the pinnae leave the 

 rachis, whilst the latter, founded upon a single and very small fragment, has no specific 

 character, and is possibly, as suggested by Heer himself,^ a fragment of P. permaformis. 

 The American Eocene^ species P. subsimplex and P. erosa, while possessing the same 



1 ' Flor. Tert. Helv.' vol. i, p. 38, pi. xii, fig. 1. 



2 ' Flor. Ter. Helv.,' vol. i, p. 39. 



3 Lesq., 'Tert. flora of America,' 1878, pi. iv, pp. 52, 53. 



