492 PTERIDOSPERMS, ETC. [CH. 



many other examples of this form of frond may be mentioned 

 T. immersa^ Nath. from the Rhaetic rocks of Scania and T. 

 virgulata from the Rhaetic of Tonkin -. 



A comparison of Taeniopteris Carruihersi or various other 

 " species " of Rhaetic fronds with the Jurassic species T. vittata 

 illustrates the slight and unimportant differences on which 

 specific separation is based. It is hopeless to attempt to draw 

 a satisfactory distinction between the numerous Taeniopteris 

 fronds from Upper Triassic and Jurassic rocks. 



Taeniopteris vittata, Brongniart. Fig. 332. 



The simple leaves to which Brongniart applied this name 

 are characteristic of the Inferior Oolite flora of -England, and 

 examples of the same type are recorded from Jurassic rocks of 

 India, Poland, the Arctic regions, Japan, China, Australia and 

 other countries''. 



Leaf linear-lanceolate, reaching a length of more than 20 cm. and a 

 breadth of 3 cm. The lamina increases gradually in breadth from the 

 base and tapers towards the apqx. Numerous secondary veins are given 

 off at right angles from a broad midrib : the lateral veins may be simple 

 or forked close to their origin, near the margin, or in the intermediate 

 portion, of the lamina. 



It is exceedingly difficult to use Taeniopteris leaves of this 

 form as evidence in regard to the Jurassic or Rhaetic age of 

 plant-bearing strata. The species T. tenuinervis Brauns, as 

 figured by Schenk* from the Rhaetic rocks of Germany and 

 Persia, and recorded from several other regions, presents a 

 close agreement with T. vitjbata. Oleandridium lentriculi- 

 forme Etheridge ^ from the Hawkesbury series of Australia is 

 another similar leaf. The species T. vittata from the Yorkshire 

 coast, represented in fig. 332, shows a well-preserved petiole 

 with a clean-cut base like that of the petioles of Oleandra 

 neriiformis and other recent ferns which are detached from the 

 rhizome by the action of an absciss-layer. 



1 Nathorst (78) PI. xix. = Zeiller (02) PI. xiv. 



' For synonymy and distribution, see Seward (00) pp. 159, 304. 

 * Sohenk (67) A. PI. xxv. See also Bartholin (92) PI. ix. fig. 7. 

 " Etheridge (942). 



