CRYPTOGAMS. 



Order.— FILICES. 

 Sub-order.— POLYPODIACEiE. 



(a.) Acrostichacea. 

 Chrysodium Lanz^eanum {Visiani). Plate I and Plate II, figs. 1 — 4. 



FoRTlsiA Lanz^ana, Fisiani. Piante fossili della Dalmazia, p. 11, pi. 1, fig. 8; pi. 2, 



figs. 1 and 5. 



Ch. fronde coriacea pinnata, pinnis lanceolatis vel ohlongo-lanceolatis, acuminatis, 

 margine undulatis vel mtegerrimis, basi sessilibus, mediis et inferioribus semi-amplexi' 

 caulibus, suhdecurrentibus, superioribus attenuatis ; nervatione Bictyopteridis simplicis 

 easappendiculata ; 7iervo primario pervalido, rigido, prominente ; nervis secundariis angulis 

 acutis variis egredientibus, congestis, abbreviatis, dictgodromis ; macuUs oblongis, pronii- 

 nentibus, pluriseriatis. 



Lower Bagshot, Studland ; Middle Bagshot, Bournemouth ; Upper Eocene, Hordwell. 



The remains are those of a large Pern closely allied to the existing wide-spread 

 tropical Chrysodium vulgare, Fee. The thick carbonised substance of the frond figured 

 in PI. I indicates its former coriaceous texture. The pinnae are lanceolate, and are 

 so closely seated on the rachis, which is 8 mm. in diameter, that their margins overlap. 

 They seem to have varied in the form of the base from cuneate to semi-amplexicaul, 

 according to their position on the rachis, and to the size and development of the frond : 

 thus, those represented in PL I have a broadly amplexicaul, almost decurrent base, and 

 are from the middle of a frond ; whilst in PI. II, fig. 2, a pinna is seen with an almost 

 acute base, and is therefore supposed to have been derived from the upper part of 

 a frond. A somewhat similar variation, but in a much less degree, is seen in the bases 

 of the pinnae of Ck. vulgare, which are, however, never amplexicaul, but always stipitate. 

 The apex is pointed ; the margin undulate. In venation it also approaches Ch. vulgare, 

 differing slightly only in the greater divergence of the angles at which the secondary 

 veins start, and in the greater diversity of form presented by the meshes of the network. 



