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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



[Mar. 20, 



indeed figured* a specimen of Ghssopteris which might at first sight 

 be supposed to show a digitate form of frond ; but on examination 

 of the drawing, it is clear that the leaves did not all grow in the 

 same plane, and that, instead of being leaflets of a digitate frond, 

 they are really simple fronds growing in a tuft (as is so common in 

 recent Ferns) from a short thick rhizoma. His description, too, 

 though not very clear, sufficiently indicates that he understood the 

 structure as I do. Such a specimen, nevertheless, ill understood, 

 may easily have given rise to the report quoted by De Zigno. 



Notwithstanding this difference in the composition of the frond 

 between the typical species of Olossopteris and of Sagenopteris, I yet 

 agree with De Zigno in doubting whether the two genera are suffi- 

 ciently distinct. In specimens of Sagenopteris Phillipsii from 

 Scarborough, I find the venation so similar to that of the Australian 

 Ghssopteris, that it would be very difficult to found a generic differ- 

 ence upon this character. Some of the Indian forms of Olossopteris 

 certainly depart more widely from Sagenopteris in their venation ; 

 but there are others again, as I shall presently mention, which show 

 truly intermediate characters. The fructification of Sagenopteris is 

 still entirely unknown ; and it is possible that, when discovered, it 

 may prove the two genera to be quite distinct ; but in the present 

 state of our knowledge, I see no sufficient reason for keeping them 

 separate. 



If it be thought expedient to reunite these genera, the name of 

 Ghssopteris certainly ought to be retained, as the older and per- 

 fectly unobjectionable. 



On comparing this Indian Olossopteris with the common Austra- 

 lian G. Browniana, allowing for the apparent differences produced 

 by the nature of the stone and the state of preservation of the 

 specimens, I can find no satisfactory specific distinction ; the 

 venation is essentially the same. We may indeed find Indian speci- 

 mens in which the meshes of the reticulation near the midrib are 

 larger and broader than in the ordinary Australian plant, and others 

 in which the veins are more strongly recurved; but, in both tbe 

 Indian and Australian plants, I find so many shades of variation in 

 these particulars, that I cannot attach much importance to them. 

 The general form varies considerably in the Australian specimens, 

 and is often quite as narrow as in those from JSTagpur ; the apex 

 also varies in the Australian plant, from very obtuse, and even retuse, 

 to rather acute, though I admit that it is never, in the specimens I 

 have seen, as acute as in the Indian. I have seen no trace of fructi- 

 fication in Australian specimens, nor is any mentioned by McCoy ; 

 on the other hand, I am unacquainted with the rhizoma of the 

 Indian Ghssopteris. In the absence of these important points of 

 comparison, we cannot feel certain of the specific agreement of the 

 two. 



With respect to the affinities of Glossopteris to recent Ferns, I 

 am not able to add anything to what Brongniart has said. The 

 form and position of the sori indicate its place either in the tribe of 

 * PI. 14 fig. 3. 



