62 BRITISH EOCENE FLORA. 



segments, bordered along their upper margin with sori, which Saporta sees reason to refer 

 to Lindsaya/ 



3. Hewardia REGiA, Ett. 8f Gard. (Page 42.) 



This is perhaps the most remarkable form obtained from Bournemouth, and is quite 

 distinct from any other Eocene Pern. The largest specimen measures 5 inches across, 

 and is probably an entire frond. The only existing Fern resembling it is Hewardia 

 Wilsoni, from Guatemala, belonging to a section of Adianfum characterised by anasto- 

 mosing venation. There are but four species of Hewardia known, all of them almost 

 peculiar to the Equatorial and Central America. The fossil differs enough, however, 

 from even its nearest known ally to entitle it to be considered an extinct type. 



4. Pteris EoCiENiCA, Ett. Sf Gard. (Page 32.) 



This form, widely spread in beds of Tertiary age, in the temperate regions of Europe 

 and America, resembles Pteris cretica and other existing allied forms of Pteris. Fossils 

 from other locaUties falling into this group have received many separate names upon such 

 characters as the toothing of the margin and the angle and forking of the veins,^ yet 

 may possibly belong even to the same species. 



P. eoccenica is, perhaps, the best type of the species, which should, under whatever 

 name, include all the forms with pinnae, whether entire or toothed, which have veins 

 running for the most part at a rather obtuse angle with the midrib, simple to twice- 

 forked, and not too crowded together. Other distinct Tertiary species are known, such as 

 P . gladifolia Q)i Ludwig, with extremely closely-set parallel veins, resembling P. pellucida 

 of the Philippines, but the group needs revision. No examples, it is important to notice, 

 of this type seem ever to have existed in any Arctic flora, although they are so abundant 

 everywhere in the beds approximating to the same ages in temperate zones. 



^ Gervais, 'Mem. de I'Acad. de Moutpellier,' vol. v, p. 311, pi. x, fig. 1. 



2 In the 'Flora Tert. Helvetica' the same form appears as P. parschlugiana, P. Gaudini, and 

 P. penncEformis, the first being separated on account of its occasionally twice-forked veins, notwith- 

 standing that the figure of P. pemiafonnis has also twice-forked veins, and because its pinnae 

 are partially denticulated. The value of the second specific character is shown by the fact that, 

 while in China and Japan, P. cretica is generally deeply toothed, it is found in many other regions with 

 a perfectly smooth margin. P. Gaudini is only separated because it is somewhat smaller. There are 

 many other forms which, judging by the published illustrations and descriptions, may possibly have to be 

 included, such, for instance, as Osmnnda eoccenica. 



