120 T^NIOPTERIS. 



V. 228. Figured by Carruthers (69), pi. vi, fig. 3. 

 Possibly a large lobed pinnule, but the specimen is not well 

 preserved. 



Bio Grande do Sul, Brazil. Pres. by X. Plant, Esq., 1869. 



V. 228^. A very imperfect example of a pinnule. 



Eio Grande do Sul, Brazil. Pres. by N. Plant, Esq., 1869. 



Genus TiENIOPTEBIS, Brongniart, 1828. 

 [Prodr. Hist. Veget. foss., p. 61.] 



Fronds or leaves simple, or more rarely pinnate, ribbon-like, 

 lanceolate, linear-lanceolate, oblong or elliptical, usually entire. 

 Apex acute, acuminate, or obtuse. Median nerve well marked, 

 extending almost to the apex. Lateral nerves arising from the 

 midrib at a very wide angle, numerous, simple or dicbotomising 

 once or several times. 



A satisfactory definition of this genus is exceedingly difficult if 

 only on account of tbe transitions which some of these fronds seem 

 to present to those of other genera such as Nilssonia. Brongniart's 

 original definition was as follows : — 



" Fronde simple, entiere, etroite, a bords paralleles, traversee 

 par une nervure moyenne, forte, epaisse, qui s'etend jusqu'a 

 l'extremite ; nervures secondaires presque simples ou bifurquees 

 a la base, presque perpendiculaires sur la nervure moyenne." 



In 1869, Schimper 1 proposed a more extended classification of 

 fronds of this type, restricting the genus Tceniopteris to certain 

 species of Palaeozoic age, and at the same time instituting a number 

 of other generic names, of which Macrotceniopteris, Oleandridiurn, 

 Angiopteridium, and Panaopsis were the chief. 



In more recent times this classification has been criticised on the 

 grounds that there is not sufficient evidence to warrant such 

 separation, and that for the present it is safer and more convenient 

 to group these fronds under the original genus Tceniopteris, using 

 that name in a wide sense. This view has been adopted by 

 Xathorst, 2 White, 3 Seward, 4 Zeiller, 5 and others, and is main- 

 tained here. 



1 Schiniper (69), vol. i, p. 600, etc. - Nathorst (78). 



3 White (93). * Seward (94), p. 124. 



5 Zeiller (82 2 ) and (02 s ), p. 59. 



