On the Swedish species of Sagenopteris Presl and on 

 Hydropteranginm nov. gen. 



In the collections of the Pa1a?obotanical Department of the Museum of Na- 

 tural History in Stockholm are some species of Sagenopteris Presl from the Mesozoic 

 rocks of southern Sweden. Most of these species have been described and figured 

 by Professor A. G. Nathorst in his memoirs on the Rhsetic floras of Scania. On 

 the basis of the Swedish material Prof. Nathorst has discussed in these papers also 

 the systematic position of the genus and arrived at the conclusion advanced already 

 by C. Fr. Braun, i. e. that Sagenopteris was a water-fern closely allied to Marsilia. 

 The same view has been adopted by Schenk, Zigno, Potonié and others, but as 

 Count Solms-Latjbach has pointed out, the evidence is far from satisfactory. Seward 

 also attributes Sagenopteris to the Filices. More recently the coalbearing layers of 

 Scania have furnished a few specimens which seem likely to throw some new light 

 on the question. Prof. Nathorst was the first to note the great resemblance of 

 these objects to the sporocarps of Marsilia and has regarded them for some time 

 back as fructifications of a water-fern. If this is really their nature, the fossils referred 

 to would afford the first actual evidence of the antiquity of the Hydropteridece. 



Some time ago Prof. Nathorst suggested to me to undertake a revision of 

 the Swedish material of Sagenopteris and to examine at the same time more closely 

 the hypothetic sporocarps. To this offer I readily assented, and the result will be 

 communicated in the following pages. I desire to express my obligation to Prof. 

 Nathorst, who has not only placéd this interesting material at my disposal, but also 

 with unremitting readiness assisted me with his great experience. Prof. C. A. M. 

 Lindman has kindly lent me, for comparative study, material of the new genus Reg- 

 nettidium Lindm. 



