[ 247 ] 



XX. 



HETERANGIUM HIBERNICUM, sp. nov. : A SEED-BEAEING 

 HETERANGIUM FROM CO. COEK. 



By T. JOHNSON, D.Sc, F.L.S., 



Professor of Botany in the Eoyal College of Science for Ireland, Dublin. 



(Plates XX and XXI.) 



[Eead Febkuaey 27. Published April 12, 1912.] 



In continuation of my endeavours to examine, in the light of recent dis- 

 coveries, the specimens, as far as available, of fossil plants recorded from Ireland, 

 I was puzzled for some time as to the nature of those described by Baily 

 under the general term of " Linear Plants" and more specifically under that 

 of Filicites Uneatus. Some of the specimens suggested leaf-stalks or rachises 

 of genera of one of the most ancient groups of Ferns — the Botryopteridese — 

 though certain markings seemed to indicate affinities with a Heterangium 

 type of plant. Figures of Filicites Uneatus are given by Baily (1) (fig. 2, 

 p. 20) in the Memoirs of the Geological Survey of Ireland (Explanation of 

 sheets 187, 195, and 196 . . . of County of Cork, 1864). The specimensi 

 figured were found in the Upper Old Eed Sandstone and Carboniferous Slate 

 of Bandon, Co. Cork. Baily says of them — "The plant remains in the slate 

 rocks of this district — provisionally named ' Linear Plants' — consist of stems 

 nearly straight, marked by fine longitudinal striations and having usually a 

 central depression, with a corresponding ridge on each side, arising probably 

 from compression, as they are more or less flattened. From these stems 

 proceed on either side diverging branches of smaller diameter, which again 

 become forked and terminate without any trace of attached leaflets ; the 

 principal stems vary in diameter from about half an inch to two lines (or 

 two-twelfths of an inch) . From the character of these plants I have no doubt 

 of their having been terrestrial and probably allied to Ferns ; there is 

 nothing to guide us, however, at present as to their exact position in the 

 vegetable series. I would propose to name them provisionally Filicites Uneatus." 

 Unfortunately the particular specimens illustrated in Baily's account are 

 temporarily mislaid, and we are compelled to form our conclusions as to their 

 nature apart from these specimens. Nathorst (2), e.g., considers that, in Baily's 



' As in other cases, I am indebted to Professor Grenville A. J. Cole, p.g.s., for permission to 

 examine these specimens from the Collections of the Geological Survey of Ireland. 



SCIENT. PEOC. R.D.S., VOL. XITI., NO. X5. 2 Q 



