F1LICES. 149 



G. Autunensis, and with our present knowledge of them they would certainly 

 appear to belong to the type of Angiopterideae ; the sori, which are formed 

 of a large number of sporangia, are elliptical, and are developed on the 

 back of the tertiary nerves. Renault's drawings of the sporangia show no 

 rudiment of an annulus. According to Schenk 1 the genus Angiopteridium 2 , 

 founded on Taeniopteris Miinsteri 3 from the Rhaetic beds, also belongs to 

 this group. The fructification which he has figured does in fact show the 

 very greatest likeness to that of our recent Angiopteris. Schenk states dis- 

 tinctly that the sporangia of Angiopteridium, like those of Angiopteris, do 

 not cohere ; the figures it is true are not decisive on this point. Since we 

 have to depend entirely on impressions of the plant, we cannot obtain 

 absolute certainty on this question ; and if it is proved that the sporangia 

 are coherent, the genus must be moved nearer to Marattia, which Schimper 4 

 thinks is its proper place. 



With Danaeaceae Stur places the genus Danaeites 5 , which was origi- 

 nally founded on a Pecopteris from the Coal-measures with a more than 

 doubtful fructification, and was afterwards somewhat more certainly de- 

 termined by him with the help of fresh specimens. The tertiary nerves 

 of Danaeites saraepontanus, Stur, like those of Danaea, bear linear sori 

 parallel to and touching one another and composed of numerous sporangia 

 in two rows ; but the boundary-lines of the cohering sporangia can be dis- 

 tinguished in the surface-view, which is not the case in the living genus. 

 Stur even maintains that he has observed indications of the characteristic 

 membranous indusial cup on pinnae from which the sori have fallen off; he 

 has not been able to determine the mode of dehiscence. Another apparently 

 allied form is Danaeites Heeri 6 from the Lias of Upper Italy. The leaves 

 of this species show the nervation of Taeniopteris, and bear sori which have 

 quite the habit of those of Danaea. Unfortunately we know only the ex- 

 ternal form ; the figure also is perhaps rather too roughly sketched, as it 

 does not show the isolated round dehiscence-spots on the sporangia men- 

 tioned in the diagnosis. Whether this is the case, or whether the diagnosis 

 says too much, can only be decided by inspection of the original specimens. 

 Further investigation is also required in order to determine how far' Danae- 

 opsis (Taeniopteris) marantacea, Heer, the fructification of which is figured 

 in Schimper 7 , belongs to the above forms. The sori of this handsome fern, 

 which is peculiar to the Keuper coal-beds, agree very fairly in habit with 

 those of Danaea. They too appear, according to Schimper 's drawings, to 

 dehisce by dot-like pores ; but it is still a question whether they cohere, as 

 in Danaea, or not. 



In connection with the long series of fossil Marattiaceae it will be as 



1 Schenk (3), t. 20. a Schimper (1), vol. i, p. 603. 3 Gbppert (1), Lief. 3 and 4, t. 4. 



4 Schimper (2), p. 86. ' Gbppert (2). f. 19. 6 de Zigno (1), vol. i, t. 25. 7 Schimper (1), t. 37. 



