FILICES. 143 



completely than that of Zeiller ; and if in these remarks I omit all mention 

 of the Ferns of the Tertiary and Upper Cretaceous formations, which, as it 

 appears, are allied at all points to living species, this proceeding will not 

 require an elaborate justification. The gap between the Mesozoic and 

 succeeding forms, which is repeatedly bridged over in the case of the 

 Coniferae, is found to be impassable in that of the Ferns in consequence 

 of our almost entire ignorance of everything relating to the Jurassic types. 

 Hence it is that in the former case we are often compelled to unite the 

 Tertiary with the later forms, in the latter we are entirely exempt from this 

 necessity. 



First of all, Stur l has proved most convincingly that the Marattiaceae 

 were much richer in species and forms, were a much more highly differen- 

 tiated family, in earlier periods of the earth's history than they are at the 

 present day. Grand' Eury 2 had already established the fact, that a large 

 number of the big multipinnate Pecopteridae and Sphenopteridae of the 

 Coal-measures belong to this family. The whole group is separated by 

 Stur according to certain characteristic marks into the subdivisions, Aphle- 

 biocarpeae, Sphyropterideae, Senftenbergieae, Angiopterideae, Hawleeae, 

 Asterotheceae, Kaulfussieae, Danaeeae, and Marattieae, of which the Kaul- 

 fussieae and Marattieae are living forms only, the Angiopterideae and 

 Danaeeae are both living and fossil, and all the rest are known only in the 

 fossil state. This arrangement, if we put aside the first two groups which 

 appear scarcely satisfactory, may be considered to be a very happy one. 

 It will be convenient to commence our survey with the Asterotheceae, 

 because this division includes the genus Scolecopteris, Zenk., the fructifi- 

 cation of which was long ago carefully examined in silicified specimens 

 from the neighbourhood of Dresden, and was distinctly recognised as 

 belonging to Marattiaceae 3 . Stur assigns to the genus Scolecopteris a 

 number of species of Pecopteris from the Coal-measures and the Permian 

 formation, as for example Pecopteris polymorpha, Brongn. (Fig. 13, D), 

 P. Cyathea, Brongn., P. arborescens, Schl., the fructifications of which are 

 also figured in Grand' Eury 4 and Renault 5 . We are not fully acquainted 

 with the form of the leaf in the long-known species Scolecopteris elegans, 

 Zenk., because we have it only in silicified fragments. The fructifications 

 also of other species have been found at Grand' Croix in the silicified state. 

 The sori, which are roundish star-shaped on the transverse section, stand 

 in a single row on the back of the tertiary nerves on each side of a secondary 

 nerve and are formed of a small number of sporangia, and each sporangium 

 has its lower half adnate to a common receptacle, which in Scolecopteris 

 elegans and its allies is prolonged into a distinct little stalk bearing the 



1 Stur (3) and (4). 2 Grand' Eury (1). :! Strasburger (1). * Grand' Enry (1). 



Renault (2), vol. in. 



