10 HALLE, ON THE SWEDISH SPECIES OF SAGENOPTERIS PRESL AND ON HYDROPTERANGITTM NOV. GEN. 



Braun's paper a statement, which appears to be of some interest. In a fragment, which 

 he believed to represent one of these sporocarps, he found a quantity of rounded 

 tetrahedral spores, but the material was löst before any figures were obtained. Schenk 

 has låter examined similar objects, but has not been able to confirm Braun's state- 

 ment. As the specimen was only a fragment, it may have been of a quite different nature. 



Schenk includes in »Die fossile Flora der Grenzschichten» Sagenopteris under 

 the Filices, but remarks, that there exists in that group no analogy with the habit 

 of the leaves of Sagenopteris. Låter on he changed, however, his view and classed the 

 genus among the Hydropteridece (3, p. 154). 



Zigno has found, in association with Sagenopteris angustifolia Zign. (1, p. 186; 

 pl. 20, figs. 2, 3), some rounded bodies, which he compares with the sporocarps of 

 the water-ferns. There is, however, no evidence at all, that this is their real nature. 



Schimper (1, p. 640) notes the resemblance of Sagenopteris to Marsilia in outer 

 appearance, but in regard to the fact, that stomata have been found on the lower 

 surface of Sagenopteris, whereas they should be confined in Marsilia to the upper 

 epidermal layer, he does not actually include the former genus under the Hydro- 

 pteridece. 



Nathorst states (1, p. 31) that stomata do occur also on the lower surface of 

 the leaves of Marsilia, a fact noted already by A. Braun (1). It is evident, however, 

 that such characters of an oecological nature are not much to be relied on in discus- 

 sions of systematic affinities. In the same paper there is a short notice, stating the 

 occurrence in association with Sagenopteris rhoifolia of some rounded bodies, the 

 surface of which shows numerous small circular elevations suggestive of spores. These 

 fossils are consequently regarded as sporocarps, and in the German edition of the 

 Pålsjö-flora (2, p. 17), Sagenopteris is placed, on these grounds, among the Marsiliacece. 

 Also Heer had independently arrived at the same conclusion after the examination 

 of one of the specimens. Thanks to more elaborate methods, Prof. Nathorst has 

 låter on been able to state, that the spore-like döts are due to resinous grains, and 

 the fossils are now regarded as seeds of Nilssonia (Nathorst, 7, p. 23). 



As Count Solms-Laubach has pointed out, (1. p. 186) all fossils ref erred to till 

 that time as sporocarps of water-ferns, are at least problematic and afford no evi- 

 dence of the existence of the HydropterideoB in the Mesozoic. 



In the låter half of the Eighties the Palseobotanical museum of Stockholm 

 received from the coal-mines of Bjuf some specimens, which seem to have a better 

 right to claim affinity with the water-ferns. Låter, similar objects were procured from 

 Hyllinge. As mentioned above, Prof. Nathorst was the first to interpret them as 

 sporocarps. He showed some of the specimens to Mr. E. A. N. Arber who also 

 admits (1, p. 228), that they certainly very strongly resemble the sporocarps of the 

 II i/dropteridece, though he is not convinced of their identity. 



The result obtained by a closer examination of these interesting fossils will be 

 communicated below. As the objects have not been found in actual connection with 

 any other fossil and cannot be ref erred to any known type, it has been necessary 

 to institute a new provisional genus for their reception. 



