Manchester Memoirs^ Vol. xliii. (1899), No. %* 



II. (a) Further Research on the Structure of 

 Psaronius, a Tree Fern of the Coal- 

 Measures. 



(6) On the Leaf-Sheath surrounding the Nodes 

 of some of the Calamites of the Lancashire 

 Coal-Measures. 



By John Butterworth, F.R.M.S. 

 [^Communicated by James Cosmo Melvill, F.L.S.^ 



Received and read October ^th^ i8g8. 

 Received in the present form Febrtiary loth, i8gg. 



(a) The coal-plant to which I wish to draw your 

 attention is not, in itself, a new plant, but the features 

 exhibited in a specimen I have recently found at Booth 

 Hill, Crompton, and also in one more recently found at 

 the same place by Mr. David Gartside, one of my fellow- 

 workers in this study, are entirely new. The arborescent 

 ferns of the carboniferous period, both of this country and 

 the continent, are at present known under the name of 

 Psaronius. Corda, in his " Flora der Vorwelt," 1845, des- 

 cribes several varieties, and the late Professor Williamson, 

 in his seventh memoir, " On the Organisation of the 

 Fossil Plants of the Coal Measures,"* describes a 

 variety which he has named Psaronius renaultii. The 

 point raised in this communication is, however, one that 

 may seriously affect present ideas regarding the structure 

 of the arborescent ferns of the coal period. I believe that, 

 up to recently, all ferns have been understood to be of 



Phil. Trans., 1875. 



May 4th, i8gg. 



