DESCRIPTION OF SPECIES. 25 



it alongside of Cyclopteris pachyrachis. Heer also has stated that Neurop- 

 teris linncecefolia resembles Cyclopteris pachyrachis. 



It will thus be seen that the Virginia plant, even in its greatly dis- 

 guised fructified form, betrays its affinity with the other plants of the genus 

 Acrostichides, some of which, as Cyclopteris pachyrachis, have not been found 

 fructified. 



Acrostichides Unnaeeefolius (Bunb. species). 



Plate VI, Fig. 3 ; Plate VII, Figs. 1-4 ; Plate VIII, Fig. 1 ; Plate IX, Fig. 1. 

 Neuropteris linncecefolia, Bunbury. 



Frond bi- or tripinnate. Bachis channeled on the upper side. Pinnae liuear- 

 elongate, subopposite or alternate. Pinnules of sterile and fertile fronds different. 

 Sterile pinnules ovate-subfalcate, acutely or obtusely terminated, distinct to the base, 

 where they are slightly rounded, attached by the entire base. Pinnules of the fertile 

 frond rounded or semicircular, slightly heart-shaped at base, and separate to the 

 insertion. Pinnules of both fertile and sterile fronds subopposite or alternate. Mid- 

 nerve of sterile pinnules stout at base but vanishing towards the apex, being dissolved 

 into branches ; lateral nerves of the same departing obliquely from the middle nerve, 

 the lower ones several times forked, the upper ones less frequently forked. On each 

 side of the insertion of the middle nerve a group of fascicled nerves is found. All the 

 lateral nerves curve strongly towards the margin. Middle nerve of the fertile pin- 

 nules stout at the insertion, and, by repeated branching in a flabellate manner, filling 

 the greater part of the pinnule. A group of lateral nerves departs from the rachis of 

 the pinna on each side of the insertion of the middle nerve, and the branches curve 

 strongly to meet the margin of the pinnules. Fructification in the form of rounded 

 sporangia placed between the branches of the nerves, and covering the under side of 

 the pinnules, giving them a granulated appearance. 



Specimens of this beautiful fern in the fructified form were obtained 

 by Sir Charles Lyell, and were described by Bunbury in the "Quarterly 

 Journal of the Geological Society," vol. hi, where he gives in plate x a 

 good figure of the plant, naming it Neuropteris linncecefolia. This specimen 

 shows well the leading characteristics of the plant, but seems to have suf- 

 fered a good deal from maceration, which has disguised the insertion of most 

 of the pinnules, rendering them too much narrowed at base. I was fortu- 

 nate enough to find, in my visit to Midlothian, on the mantel of an old 

 gentleman who had, thirty years before been a miner of coal in this vicinity, 

 a large slab of very fine-grained shale, of light gray color, on which were 

 large impressions of several species of plants, beautifully preserved, with 

 all the carbonaceous material of the plants in place. This slab had been 



