[ 211 J 



XIIT. 



BOTHIWDENDRON KILT0RKEN8E, Haught. Sp. 

 ITS STIGMAEIA Al^D CONE. 



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

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



(Plates XIV-XVIII.) 



[Read December 16, 1913. Published February 27, 1914.] 



In a paper ovi'Bothrodendron kiltorkense I sought to show that Bothrodendron 

 agrees witli Lepidodendron and Sigillaria in the possession of a rhizomatous 

 or rliizophorous organ (1) indistinguishable from a form of fossil commonly 

 called Stigmaria. Recent excavations at Kiltorcan have supplied material 

 which seems to leave no room for doubt tbat this is the case. The specimen 

 figured (Plate XIV) is an impression, at one end of which are the typical 

 Stigmarian appendages. Their characteristic scars are visible higher up on 

 a wrinkled surface-marking wliich gradually changes to one like that seen 

 in the ordinary aerial stem of Bothrodendron kiltorkense. The wrinkled 

 surface, so well seen here, is to be attributed to shrinkage of the surface due 

 to the collapse of tlie chambered cortical tissue of this fossilizing marsh-plant. 

 At one point (PI. XIV, a, a) there is a horizontal zigzag line marking 

 off the more wrinkled lower region from the upper smoother surface. 

 On this latter surface one can see clearly oblique rows or spirals of 

 small rounded leaf-scars wide apart. The leaf-scars alternate with one 

 another above and below, or are quincuncially placed (Plate XV, fig. 2). 

 Thus in one continuous impression we have an aerial stem showing leaf- 

 scars, with a sharp line of demarcation from the forking Stigmarian rhizome 

 with its root appendages. The illustration is of interest in its bearing on a 

 view that the Stigmarian appendages, wliich are also quincuncially arranged, 

 may be modified leaves. 



The horizontal streak represents, I take it, the ground- or mud-level of 

 the marshy soil in which the Bothrodendron grew. It is worthy of note that 

 the leaf-scar region shows that zonation to which I have called attention 



SOIENT. PEOO. R.D.S., VOL. XIV., NO. XIII. 2 I a 



