On a "Fern" Synangium. By D. M. S. Watson. 3 



General Conclusions. — The preceding description seems to show 

 that the fructification belongs either to the Ferns or to the Cyca- 

 dofilices, and I think that two years ago no one would have 

 hesitated to say that it belonged to one of the Marattiaceae. 



Now, however, in view of Mr. Kidston's discovery that Crosso- 

 theca, formerly considered to be Marattiaceous, is really the male 

 fructification of Lyginodendron* whose female fructification is, 

 of course, the seed Lagenostoma,^ it seems safer to regard it as 

 of uncertain position, although belonging to either the Ferns or the 

 Cycadofilices, and I think most probably to the Ferns. 



For this reason I have put the word " fern " in inverted commas 

 in the title. 



Association. — The slide contains, amongst other things, Lygino- 

 dendron, " Cordaites " leaves, and a fern leaflet, which I have not 

 seen elsewhere. This leaflet apparently is a Pecopteris ; its structure 

 is quite ordinary, but it bears unicellular short pointed hairs on the 

 lower surface. The edges are strongly recurved. 



Comparison ivith other Synangia. — The synangium with which 

 one instinctively compares this, is that known as Ptychocarpus 

 unitus Brongn., which occurs as impressions in the Upper Coal 

 Measures of Eadstock, in Somersetshire, and with structure pre- 

 served in the silicified material from Autun. 



It has been well described by Eenault.J 



In Ptychocarpus, however, the receptacle is not hollowed out 

 into a cup at the top, and contains a vascular bundle rising 

 " jusqu'au sommet du synangium." 



There is no cup of tracheids at the base in Ptychocarpus, which 

 also has larger spores, measuring 20 fi. 



In the recent genus Kaulfussia there is a very similar cup of 

 tracheids in the sterile tissue at the base of the synangium. This 

 is figured by Bower. § In the case of Kaulfussia the tracheids seem 

 to be more irregularly placed than in the fossil genus, and do not 

 approach so closely to the bases of the sporangia. The Kaulfussia 

 synangium also resembles the fossil in the cup at the top, and in 

 its circular form. 



There is, I think, no British synangium described with which 

 this can be compared, and I think that it is advisable to give it a 

 name for convenience of reference. With this in view, I propose 

 that it should be referred to as Cyathotrachus altus — in allusion to 

 the cup of tracheids at the base, and to the great relative height of 

 the synangium. 



* R. Kidston, paper read Roy. Soc. July 8, 1905, published Nature, July 13, 

 1905. t Oliver and Scott, " Lagenostoma Lomaxi," Phil. Trans., 1904. 



X Renault, " Bassin houiller et permien d'Autun et d'Epinac," part II. p. 9. 



§ Bower, " Studies in the Morphology of the Spore-producing Members of 

 Marattiace;e," Phil. Trans., series B, 1897. 



B 2 



