FOSSIL FLORA OF THE STAFFORDSHIRE COAL FIELDS. 109 



If these characters were constant, then there might be ground for the separation 

 of Neuropteris gigantea Sternb. into the proposed two species ; but unfortunately they 

 appear to be very inconstant. 



Between the sickle-shaped and " straight " pinnules there is every graduation 

 of form. In fact, the pinnules of Neuropteris gigantea, to use the old name 

 collectively, are extremely variable. Almost invariably the pinnules are slightly 

 oblique — that is, one side is slightly convex and the other concave. This is seen in 

 the figure given by Zeiller,* which is the type of Neuropteris Zeilleri ( = Neuropteris 

 pseudogigantea) Potonie. In fact, a pinnule of "Neuropteris gigantea" with straight 

 sides is very seldom seen. 



The pinnules of Neuropteris gigantea, like others of the genus, are articulated 

 to the rachis, and, like our Osmunda regalis, seem to have been shed when the fronds 

 ripened to decay. Hence it is comparatively seldom that one gets large specimens 

 of this species showing the pinnules attached to the rachis. The much more common 

 mode of occurrence is to find the isolated pinnules scattered over the surface of the 

 shales containing them. 



Among these isolated pinnules it is easy to find connecting forms from Neuropteris 

 gigantea Sternb. to Neuropteris pseudogigantea Potonie. As far as the form of the 

 pinnule is concerned, it seems impossible on this character to separate the " species." 

 Even on the type-figure of Sternberg t some of the pinnules are falcate or sickle- 

 shaped while others are straight, and a few "straight" pinnules also occur on the 

 specimen figured by Potonie himself. J Accordingly, if you removed the pinnules from 

 the rachis of these two specimens and scatter them on a slab, you would find both 

 species represented. As to size, the pinnules vary much even on the same specimen. 



In regard to the nervation, neither is this constant in the two forms, for I possess 

 a British specimen (No. 4519) which is typical in all respects with Neuropteris gigantea 

 Sternb. (Potonie), except that the mid-vein extends well up the pinnule and does 

 not break up into veinlets at or near the base. I have also a specimen from Prussia 

 showing the same character. An anastomosing of the veins I have never observed 

 to occur in any form of Neuropteris gigantea. 



I have therefore failed to satisfy myself as to the specific value of Neuropteris 

 pseudogigantea Potonie, and therefore include it with Neuropteris gigantea Sternberg. 



Some specimens of Neuropteris gigantea from the South Staffordshire Coal Field 

 are given on PI. VI. figs. 1 to 7, and these illustrate the form almost invariably found 

 there. All the examples shown on the Plate are preserved in ironstone nodules, and 

 show the great beauty with which the details of structure can be preserved in 

 this matrix. 



At fig. 1 a fragment of an ultimate pinna is given. This specimen would probably 

 fall to be placed under the Neuropteris pseudogigantea Potonie by those who uphold 



* Flore f oss. bassin houil. d. Valen., pi. xlii. fig. 1 ; well seen in fig la. 

 t PI. xxii. t PI. iii. 



