GLOSSOPTEUIS. 45 



39,149. Text-fig. 14. 



Another and similar piece of pinkish scale, on which occnr 

 impressions, chiefly of the larger fronds of G. Browniana. There 

 are also a fairly good example of a strongly convex scale-frond, 

 and a few more fragmentary specimens of the same leaves on 

 which prints of sori may possibly occur. Two groups of the 

 sporangium dike organs are found, as well as other more obscure 

 examples. Some of these have dehisced (Text-fig. 14), while 

 others again are arranged in a sorus-like manner. 



Port Stephens, New South Wales. Odinheimer Coll. 



SPECIES OF GLOSSOPTERIS. 



A large number of species of Glossopteris have been described by 

 various authors, in many cases on quite insufficient grounds. It is 

 a most difficult and thankless task to attempt a general revision of 

 these specific determinations, for it is almost impossible to obtain 

 any definite aggregate of characters to serve as a standard in 

 dealing with details confined to the shape of the sterile frond and 

 its nervation ; the characters on which any classification must at 

 present be based. There has been considerable difference of opinion 

 already on this subject. In 1828, Brongniart 1 described an Indian 

 and an Australian leaf, which he regarded as varieties of a species 

 to which he gave the name Glossopteris Browniana. Some years 

 later Schimper 2 raised both these forms to specific rank, as 

 G. Browniana and G. indiea respectively. Since then Feistmantel, 

 especially, has described many fronds as new species, some of 

 which, such as G. communis, are now admitted to be unworthy 

 of separate designations. In more recent times Professor Zeiller 3 

 has upheld in several cases the specific rank of certain fronds which 

 Mr. Seward 4 has been inclined to regard as hardly more than 

 varieties. 



The difficulty arises from the fact that, as in other fern-like 

 plants buth recent and extinct, there existed a considerable 

 variation in the form and shape of the leaf of Glossopteris, and in 

 the details of the nervation, even in fronds which there is reason 



1 Brongniart (28 2 ), p. 223. 2 Schimper (69), p. 645. 



3 Zeiller (96'), (02'). * Seward (97 1 ). 



