THE JURASSIC FLORA OF SUTHERLAND. 665 



No decisive evidence has been obtained as to the affinity of this fern, though the 

 facts favour the view that it is closely allied to the genus Gleichenia. Such specimens 

 as those represented in figs. 50-52, PI. III., 88, 89, PI. V., bear a close resemblance to 

 the pinnae of recent species of Gleichenia, as also to some of the Lower Cretaceous 

 species figured by Heer : the form of the soral casts is consistent with this comparison. 

 A piece of collateral evidence is furnished by the petrified fragment, presumably of a 

 stem, represented in figs. 42-43, PL III., and described as Gleichenites Boodlei. This 

 specimen has no pinnules in connection with it and cannot therefore be assigned to the 

 same species as the detached pinnae of G. cycadina. The Gleicheniaceae are known to 

 have been represented in European floras during the Lower Cretaceous period : Heer's 

 Greenland specimens of well-preserved fronds and the anatomical characters discovered 

 by Dr Bommer in stems from Wealden beds in Belgium constitute decisive proof.* 

 Some at least of the specimens which I described in 1894 as Leckenbya valdensisf 

 from the Wealden of Sussex are identical with the Culgower fern ; there is, however, 



A. B. 



Text-Fig. 5. — Gleichenites cycadina (Schenk). 



A. Sterile pinnules ( x 5). (Arber collection, 496.) 



B. Sterile pinnules ( x 4). (Arber collection, 554.) 



little doubt as to the identity of the German Wealden species described by Schenk as 

 Alethopteris cycadina with the Sutherland type, which is therefore referred to the 

 older species founded in 1871. The sori of the German specimens appear to agree 

 with those represented in fig. 9 5 A, PL V. The small fragment figured by Schenk as 

 Sphenopteris delicatissima\ may be a piece of the distal end of a pinna of Gleichenites 

 cycadina, and some of the examples identified by Schenk as Pecopteris Dunkeri are 

 indistinguishable from the Culgower fern. The prominent basal lobe of the pinnules 

 of Gleichenites cycadina constitutes a distinguishing feature between this type and 

 several species of the same genus described from Jurassic and Lower Cretaceous 

 localities. A comparison may be made with the following species : Gleichenites sp. 

 described by Nathorst § from Upper Jurassic beds in Spitzbergen ; pieces of pinnae 

 from Wealden rocks in Japan referred by the same author to Pecopteris Geyleviana ; || 

 Heer's Greenland species Gleichenites delicatula ; IF Fontaine's plant from the Lower 

 Cretaceous of California figured as Gleichenia Nordenskioldi Heer ; ** Feistmantel's 

 Pecopteris tenera tt from the Jurassic of Cutch, India ; also the Indian fern Pecopteris 



* Seward (10), p. 353. t Seward (94), p. 145 ; (95), p. 225. 



% Schenk (71), pi. xxvii. fig. 3. § Nathorst (97), pi. ii. figs. 15, 16. || Nathorst (90), pi. iv. fig. 3. 



1 Heer (75), pis. ix., x. ** Ward (05), pi. lxv. tt Feistmantel (76), pi. iii. fig. 5. 



