XXXIX] 



COMPARISON 



97 



coenosori,as in Onychinui and Doryoptcris: while in Saffordia and Trachypteris 

 a spread of the fertile tract of the coenosorus inwards from the margin 

 led again to an Acrostichoid state, as in Acrostichum praestantissivmin 

 and aiireinn. But these several changes, following sometimes on linkage, 

 appear to have arisen in the Gymnogrammoid series quite independently 

 of the similar linkage and Acrostichoid development in the Pteroid Ferns. 

 The two series may be held to have progressed along parallel lines, though 

 with many features in common. This has led to those systematic and termino- 

 logical difficulties which have always beset the Pteroid and Gymnogram- 

 mioid phyla. These can best be resolved by approaching their classification 

 from the evolutionary point of view. In the present case we shall trace the 

 Pteroid Ferns from a bi-indusiate Dicksonioid origin: but the Gymnogram- 

 moid Ferns from an Osmundioid-Schizaeoid source.-vvithout any specialised 

 indusium. 



No attempt will here be made to group the Gymnogrammoid Ferns 

 according to any exact phyletic relations of the genera one to another, or 

 to ancestral forms. This must be left over till further enquiry shall have 

 supplied the necessarily detailed knowledge. Consequently the table of 

 genera given below is more in the nature of a suggestive catalogue than of 

 a phyletic scheme. But speaking quite generally those earlier on the list 

 link with Plagiogyria and the Osmundaceous stock: those named later show 

 rather a Schizaeoid affinity. 



THE GYMNOGRAMMOID FERNS 



I. Relatively Primitive Genera. 



(i) Llavea Lagasca, 1816 



(ii) Cryptogramine ^. Vixown, \^2i 

 (iii) Onychium Kaulfuss, 1820 

 (iv) Jamesonia Hook, and Grev., 1830 ... 



(v) Ceratopteris Brongniart, 1821 



II. Central Group of Genera. 



(vi) Pterozonium Fee, 1850 

 [(vii) Syngrainme J. Smith, 1845 (see Chapter XLVi) 

 (yiii) A uogramme Link, I ii4i 



(ix) Gy7n7wgram7/ie Desvaux, 181 1 



(x) Couwgm7njue Fee, 1 8 so 



(xi) Heinionitis \J\.\\x\e, 1753 ••• 



(xii) Gyiiinopteris Bernhardi, 1799 

 (xiii) Ceropteris \J\\-\V, i8\i 

 (xiv) TrisDieria Fee, 1850 



I species. 

 4 species. 



6 species. 

 14 species. 



1 species. 



2 species. 

 16 species.] 



9 species. 

 50 species. 



2 species. 



8 species. 

 12 species. 



7 species. 

 2 species. 



