CRYPTOGAM^.. 



Order.— FILICES. 



SuB-OEDER.— POLYPODIACEiE. 



(a.) AcrosticJiacea. 



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



FoRTisiA Lanz^ana, Fisiaiii. Piante fossili della Dalmazia, p. II, pi. l,fig. 8; pi. 2, 



figs. 1 and 5. 



Ch. fronde coriacea j^innata, pinnis lanceolatis vel ohlongo-lanceolatis^ acuminatis, 

 margine undulatis vel inte^erriviis, basi sessilibus, mediis et iiiferioribus semi-amplexi- 

 caulibus, sichdecurrentibus, suijerioribas atteniiatis ; nervatione Dictyopteridis simpUcis 

 exappendiculata ; ne^-vo jjrimario pervalido, rigido, prominente ; nervis secundariis angulis 

 acutis variis egredientibus, congestis, abbreviatis, dictgodromis ; maculis oblongis, promi- 

 nentibus, pluriseriatis. 



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



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

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

 in PI. I indicates its former coriaceous texture. The pinnas 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 pinnge of Ch. vulgare, which are, however, never amplexicaul, but always stipitate. 

 The apex is pointed ; the margin nndulate. 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. 



