[MATTHEW] UPPER DEVONIAN PLANTS 109 



tached ones are not uncommon in the rock, as well as rounded depres- 

 sions in the sporophyll, showing their seat of origin. They all show 

 a thick carbonaceous coat — the sporophyll occasionally seen broken 

 through, and revealing an enclosed cavity. 



"The presence of so many megaspores in one megasporangium 

 in Bothrodendron {C y do stigma) Kiltorkense is interesting, and adds 

 to the likeness, first noted by Schimper, of the Kiltorcan sporophyll 

 to Isoëtes. An additional feature deserves mention. I have frequently 

 noticed at the point of the union of the fertile base with the sterile 

 lamina on the upper side, a distinct carbonaceous plate, semilunar in 

 shape. In some cases the plate is absent, but its extent is indicated 

 l»y an impression, limited by a curved ridge on the sterile part of 

 the sporophyll, above the spore bearing base. I take this to be the 

 ligule, coming as in Isoëtes between the sporangium and the sterile 

 distal part of the sporophyll. 



"I have attempted in the accompanying figure (PI. I, fig. 3) a 

 restoration of a female sporophyll. I had decided to omit this 

 suggestion of the possible presence of a ligule, when I saw that Heer 

 states that every sporophyll of Bothrodendron {Cyclostigma) Kiltor- 

 kense appeared to have possessed an oval papilla, or flap, lying between 

 the fertile base and the sterile bristle like appendage. 



"I give (Plate III, fig. 3) a figure of the appearance presented by 

 one megaspore, and feel emboldened to do so, owing to the discovery 

 by R. C. McLean^ of the presence of the megaspore of B. mundum 

 (Coal Measures) of a prothallus protecting in a manner not unlike 

 that in the germinating megaspore of a Pilularia or lanceolate Lycopod. 

 There is a general agreement in the possession of a heterosporous cone^ 

 OÎ B. {€.) Kiltorkense and B. mundum. 



A year after his main article on Bothrodendron {Cyclostigma) 

 Kiltorkense was written Prof. Johnson discovered the rhizome and 

 cone of this species and thus was able to give a fairly complete account 

 of its parts. 



Rhizome (Plate III, fig. 1). 



This was found to agree with those known to be connected with 

 Lepidondendron and Sigillaria. The specimen he found was an 

 "impression" at one end of which are typical( ?) Stigmaria appendages. 

 "Their characteristic scars are visible further upon the wrinkled sur- 

 face, which gradually changes to that seen in the ordinary aerial stem 

 of the species. The wrinkled surface so well seen here is to be attri- 

 buted to the shrinkage of the surface due to the collapse of chambered 



^Two fossil prothalli from Lower Carboniferous (New Phytologist, Vol. IX, 1912. j 

 ^The former is the earliest examples of heterospory known. 



