﻿1851.] BUNBURY FOSSIL PLANTS OF SCARBOROUGH. 



187 



ing from a tufted rootstock, it was probably a near ally of some 

 species which have been found in the Wealden deposits of Northern 

 Germany ; and it may have been related either to the recent Polypodia, 

 or to the Blechna and Lomarice, to which latter perhaps it would have 

 a nearer resemblance. On the other hand, a frond of the form 

 which seems to be indicated by Dr. Murray's specimen would resemble 

 the fossil genera Laccopteris, Goepp., and Andriania*, F. Braun, to 

 one or other of which it is very probable that our plant might be re- 

 ferred if its fructification were known. The described species (very 

 few in number) of both these groups belong to the Lias of the district 

 of Bayreuth. 



I have only to add, that the veins, in all the specimens I have seen 

 of Pecopteris ccespitosa, are ill preserved, but appear to resemble 

 those of P. Sulziana, sl species belonging to the Gres bigarre. 



5. ACROSTICHITES WlLLIAMSONI. 



Pecopteris Williamsonis, Ad. Br. Hist. Veg. Foss. i. p. 324. t. 110. 

 f. 1, 2; L. & H. Foss. Fl. t. 126. 



curtata, Phillips, Geol. Yorks. t. 8. f. 12. 



Acrostichites Williamsoni, Goeppert, Syst. Filic. Foss. p. 285. 



I mention this common and well-known plant of the Yorkshire 

 Oolite, merely for the sake of remarking, that I think it may be re- 

 tained as a genus distinct from Pecopteris, under Goeppert' s name of 

 Acrostichites. It is true that the venation affords no character by 

 which it can be known from the Neuropteroid section of Pecopteris ; 

 and the peculiar form of the leaflets would afford only a specific cha- 

 racter ; but the fructification is so remarkably different from that of 

 all other Pecopterides which have yet been found in a fertile state, 

 as to show that the plant naturally belongs to a different group ; and 

 at the same time it is of such frequent occurrence, that I see no 

 practical inconvenience in taking it for the basis of a generic character. 

 That the small round bodies which so frequently cover the back of 

 the leaflets are really capsules {sporangia), and not scales or other 

 mere appendages of the cuticle, is proved by a specimen in Dr. Mur- 

 ray's possession, where these capsules are so well preserved, so little 

 crushed or distorted by pressure, that their form and structure, in 

 which they quite resemble those of recent Ferns, can be distinctly 

 seen with a lens. I observe also in some specimens, that the lower 

 leaflets of the pinnse are entirely covered with these bodies, the upper 

 quite free from them, and that on some of the intermediate leaflets 

 they cover a part only of the surface, but without forming definite 

 spots or lines. All this is exactly analogous to what is seen in various 

 recent Ferns of the Acrostichum group. It is true that in that tribe, 

 the fertile fronds or leaflets are usually (but not always) different in 

 shape from the barren ; nor am I able to point out any recent species 

 belonging to it, which has precisely the same arrangement of veins 

 as this fossil. The name Acrostichites, therefore, must be taken as 

 implying an affinity with the genus Acrostichum in its old and ex- 



* See the descriptions of these genera in Brongniart's Tableau des Genres, p. 29. 



o 2 



