2 3 o SCIENCE PROGRESS 



specimens from Virginia, belonging to a typical Lower Car- 

 boniferous frond-genus, Ancimites, better known in this country 

 under the name Adiantitcs, which bore seeds on the fronds. 

 In this case the lamina of the fertile frond was reduced, as 

 compared with that of the sterile, and the seeds appear to 

 have had a distinct marginal wing. Thus seed-bearing fern-like 

 plants have been traced back so far as Lower Carboniferous 

 times. 



An equally interesting discovery, and one perhaps of greater 

 significance at the present time, was made by the veteran French 

 Palaeobotanist, M. Grand'Eury, 1 in the following year (1905). 

 The frond-genus shown, in this instance, to belong to a 

 seed-bearing plant, is that known as Pccoptcris, which is 

 admittedly very fern-like. It occurs commonly in the higher 

 zones of the Upper Carboniferous and in the Permian. Pro- 

 bably of all the fern-like genera found in these rocks, Pccoptcris 

 was the one which was least suspected of being a Pterido- 

 sperm, for many species have been known for a long time 

 in the fertile state, and, so far, the fructification has invari- 

 ably proved to consist of sporangia, which may be closely 

 compared with those of a family of living ferns, the Marattiacece. 

 Yet M. Grand'Eury has shown that at least one Pecopterid, 

 P. Pluckeneti, Schl., bore seeds, and that the seeds were attached 

 to the lower surface of a fertile frond, 2 which scarcely differed 

 as regards the lamina from the sterile leaf. It is true that this 

 species is not a very typical member of the genus. But it seems 

 quite possible that other Pecopterids may have borne seeds, 

 and that some of the fructifications, at present regarded as 

 sporangia, comparable to the organs of the homosporous ferns 

 which they so closely resemble, may have been in reality the 

 male organs of Pteridosperms. However, for information on 

 this point we must look to the future. 



This completes the list of Pteridosperms which have been 

 discovered during the last three years. There are, however, 

 many genera which at present rest under the strong suspicion 

 of having also been members of this race, and not ferns, but 

 in these cases the material at present available is not sufficient 

 to place the matter beyond doubt. In most of these good 

 evidence of continuity between the seed and the frond is at 

 present lacking. 



1 Grand'Eury, 1905. 2 See Zeiller (1905), fig. 7 on p. 725. 



