1 1 6 WEICHSELIA. 



18*3. Lonchopteris MantelU, Renault, Cours bot. foss. vol. iii. p. 167. 



1888. Weichselia Ludovica, Schulze, Flor. subhercyn. Kreid. p. 14. 



1889. Lonchopteris Mantelli, Bristow," Geol. I. Wight, p. 258. 



1890. Weichselia erratica, Nathorst, Arch. Ver. Freund. Nat. Mecklenb. 



Jahr. xliv. p. 1, pi. i. figs. 1 and 2. 



1890. Pecopteris Geyleriana (in part), Nathorst, Denkschr. k. Ak. Wiss. 

 math.-nat. Cl. vol. Ivii. p. 49, pi. iv. fig. 3 (not the other figures 

 of this species) . 



Type. Fragments of pinnae ; pinnules showing venation. The 

 specimens on which the genus Weichselia was founded are much 

 larger, and consist of long pinnaB attached to a broad rachis ; no 

 venation shown. 



The first diagnosis of Weichselia Ludovicce is that given by 

 Stiehler in 1857; the earlier definitions of the English species, 

 Lonchopteris Mantelli, were founded on much smaller specimens 

 than those which Stiehler had before him : 



" Frons bipinnata, expansa, maxima (5-6-8 pedalis) ; rhachis 

 valida, profunde sulcata, apicem versus tenuissime excurrens ; 

 pinnae terminales subverticales, elongatae, anguste lineares, remotae 

 (distantes), reliquae horizontales, convexae, approximatae, lineari- 

 lanceolatae, ad 18 poll, usque longae, iV poll, latae, omnes basi 

 discretae; pinnulae perbreves, oblongae, obtusae, integerrimae, approxi- 

 matae, fructiferae medio, canaliculatae, ambitu contractae, steriles 

 subplanae." 1 



The following definition includes most of the important characters 

 in this peculiar type of fern : 



Frond bipinnate, rachis broad and rigid, pinnae alternate, very 

 long, of uniform breadth and with prominent axes ; pinnules entire 

 with obtusely rounded apex, a midrib and reticulate secondary 

 veins, oblong, except towards the distal ends of pinnae, where they 

 become more or less triangular in shape and have pointed apices, 

 attached by the entire base, separate and not confluent ; the stiff 

 and thick pinnules are usually inclined towards the axis of the 

 pinna, and the two rows form with the axis an open V instead of 

 lying in a horizontal position. 



The earliest figures and description of Weichselia Mantelli 

 (Brong.) are usually attributed to Mantell in the year 1824; the 

 paper to which reference is made was written by Stokes and Webb, 



Palaeontographica, vol. v. 1857, p. 75. 



