BY R. ETHERIDGE, JUN. 245 



the two genera. As a rule the leaflets of Sagenopteris are much 

 smaller than those of Glossopteris, but in S. goppet'tiana, Zigno,* 

 they are large and very Glossopteris-like. 



From the foregoing remarks it is manifest how difficult it is to 

 distinguish between the fronds of the two genera, if the venation 

 is alone relied on, except in extreme forms of either. 



Amongst the .species at present included by authors in 

 Sagenopteris there are three distinct types in the form and method 

 of attachment of the leaves : — 



a. Leaves elliptical or obpyriform, sessile, or hardly petiolate, 

 e.g. : Sagenopteris rhoifolia, Presl., (the generic type) ; 'S". goepiier- 

 tiana, Zigno ; S. undulata, Nath. 



h. Leaves lanceolate, petiolate, e.g. : Sagenopteris Phillipsii, 

 L. and H. 



c. Leaves lanceolate, sessile, e.g. : S. (?) longi/olia, Feist. 



With regard to the first section, when the leaves are found 

 attached to the stalk, as is very frequently the case, the whole 

 facies of the plant, plus its venation, is so manifestly different 

 from our present fossil that we do not think there need be any 

 doubt of the distinctness of the two. 



As to the second section, the matter is not so clear. There 

 the form and arrangement of the leaves, together with the more 

 or less persistent mid-rib, are so markedly that of our Mudgee 

 plant (PI. XVIII. fig. 1) that one is led to doubt the wisdom of 

 separating the latter from it, were it not for the petiolate nature 

 of this section. On the other hand, the sessile condition of the 

 leaves in the Mudgee fossil distinctly allies it to the third, or 

 section c. After all, as in so many other instances, generic separa- 

 tion will probably have to depend on the fructification when that 

 shall become more thoroughly known. For this, however, we 

 must await further discoveries. 



* Flora Foss. Form. Oolithicae, i. p. 188, t. 22, f. 1 and 2. 



