486 PTERIDOSPERMS, ETC. [CH. 



name to apply to fragments of fossil leaves of Mesozoic age. 

 Taeniopteris is, however, distinguished from the Cycadean genus 

 by the greater prominence of the rachis, also by the dichotomous 

 branching of the secondary veins, usually close to their origin 

 and at varying distances between the axis of the frond and the 

 edge of the lamina. The genus Taeniopteris, though most 

 abundant in Rhaetic and Jurassic strata, occurs also in Upper 

 Carboniferous and Lower Permian rocks. The generic name 

 Macrotaeniopteris instituted by Schimper^ has been used for 

 leaves differing only in size from the usual type of Taeniopteris, 

 but there is no adequate reason for its retention. 



The species included in Taeniopteris afford no satisfactory 

 evidence as to their systematic position. It is obviously unwise 

 to adopt such generic titles as Oleandridium, Marattiopsis, etc., 

 merely because of resemblance in the venation of sterile 

 fragments to Oleandra or Marattiaceous ferns. 



Some specimens of Taeniopteris fronds described by 

 Mr Sellards^ from Permian rocks of Kansas, which are referred 

 to later, have furnished unconvincing evidence of reproductive 

 organs. 



Taeniopteris multinervis, Weiss. Fig. 329, A, B. 



The late Dr Weiss^ instituted this species (which he desig- 

 nated Taeniopteris multinervia, though the specific name multi- 

 nervis is constantly used) for a fragment of a leaf from the Lower 

 Permian of Lebach characterised by numerous forked veins 

 given off at right angles from a prominent rachis (fig. 329, B). 

 This type of frond is recorded from the Permian of Trienbach 

 (Alsace) by Zeiller*, by Renault^ and Zeiller^ from the Upper 

 Carboniferous of Autun, and from other localities. The lamina 

 of the simple leaf reaches a breadth of 6 cm. and a length 

 of 40 cm. (fig. 329, A); the numerous secondary veins (25 — 36 

 per cm. of lamina") are either at right angles to the rachis 

 or given off at an acute angle. The mesophyll consists of 



1 Schimper (69) A. p. 610. " Sellards (01). 



3 Weiss, C. E. (69) p. 98, PI. vi. fig. 13. * Zeiller (94) p. 169. 



Renault (96) A. p. 1. « Zeiller (90) Pis. xii. xin. 



