502 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Having now considered the several points of similarity be- 

 tween the HymenophyllacecB and the Mosses, and having 

 recognised where the chief difficulty lies in imagining a transi- 

 tion from the Bryophyta of the present day to the Filmy Ferns, 

 we may turn to the other end of the Filicineous series, and 

 discuss the probability of the Eusporangiate Ferns being the 

 more primitive type. It may be stated at once that the affinity 

 of the Eusporangiatce is rather to certain Liverworts than to the 

 true Mosses, and the whole question practically resolves itself 

 into this — whether the affinity of the HymenophyllacecB to the 

 Musci, or of the Eusporangiates to the Liverworts, be the nearer 

 and the truer one. 



Comparing the gametophyte of AntJioceros with that of 

 Marattia (or even Ophioglossum, though this is too imperfectly 

 known), the similarity of general conformation is obvious 

 enough ; but especially the deeply immersed position of the 

 archegonia in both cases is worthy of remark. The similarity is 

 here quite as great as that above traced between the gamete - 

 phytes of the Hymcnophyllaccce and Mosses. But I do not 

 propose to draw detailed comparisons oetween any one Euspo- 

 rangiate Fern and any one of the Liverworts, but rather approach 

 the question from a more general point of view. The following 

 general reflections appear to me to deserve consideration: — 



1. Of the three phyla of Vascular Cryptogams the two 

 others — the Lycopods and Equiseia — are eusporangiate. If, as 

 is most probable, these, though now distinct, had a common 

 origin with the Ferns, it would be reasonable to assume that 

 the original Ferns would also be eusporangiate, and the lepto- 

 sporangiate type be of more recent origin. Colour is lent to 

 this assumption by the absence of any intermediate steps leading 

 to the leptosporangiate type, excepting through the Eusporan- 

 giatce themselves. 



2. If the Eusporangiatce were derived from the Liverworts, 

 the bulky sporangium is already foreshadowed by the capsule 

 itself, and it is hardly going too far to say that the capsule of a 

 J linger niannia or a Marchantiais one eusporangiate sporangium. 

 Thus, by whatever line of development the more complex sporo- 

 phyte, with its leaves, stem, and root, was derived, the bulky 

 eusporangiate type is probably the original one. 



3. Passing on to the apical meristems, the characters of these 



