Johnson — Bothrodendron kiltor-kense. 213 



sporophylls are female, and each bears a large sessile megasporangium 

 containing numerous megaspores. The upper sporophylls are male, and 

 their sporangia contain microspores. The cone is Lepidostrobus-like and 

 not Selaginella-like, as is the Bothrodendron {Bothrostrohus) mundum cone 

 described by Watson. 



The cone of B. kiltorlcense is a highly specialized structure, more differ- 

 entiated than the strobilus of Lycopodium, and especially than that of 

 L. Selngo. The presence in the Devonian of such well-organized cones so 

 clearly marked off from the sterile foliage shoot should give pause to the 

 entertainment of the theory of the derivation of foliage leaves by sterili- 

 zation of fertile sporophylls, In the case before us it seems simpler to 

 regard the cone as arising by the development of the sporangium on the 

 apical foliage leaf of the shoot, with the modification of form resulting 

 from this additional function, than to accept the view that the cone — a 

 circumscribed terminal region — is all that is left of the fertile sporophylls, 

 the others having, by loss of their sporangia, become sterile foliage leaves. 



In support of this latter view is the case of Plnakodendron Ohmanni, Weiss, 

 as described by Kidston (4). In his well-illustrated account Kidston shows 

 that the only diffei-ence between the sterile and fertile regions of this 

 heterosporous Carboniferous Lepidophyte is the presence of four-spored 

 megasporangia on the fertile leaves. The species shows the recent Lycopodium 

 Selago type of ' strobilus.' 



Bibliography. 



1. Johnson, T. — " On Bothrodendron {Cyelostigma) kiUorkense, Haughton, 



sp." Sci. Proc. R. Dublin Soc. Vol. xiii (n. s.), 1913, p. 500. 



2. White, D. — " A remarkable Fossil Tree-trunk from the Middle Devonic 



of New York." New York Museum, Bulletin 107 : Geological 

 Papers, Albany, 1907. 



3. Kkejci, J. — " Notiz iiber d. Eeste von Landpflanzen in der bohmischen 



Silurformatiou." (Sitz.-Berichte d. konigl. Bohm. Gesellsch. d. 

 Wissensch. in Prag, Jahrgang, 1879, s. 203.) 



[The few lines of unillustrated description of this interesting 

 primitive form seem inadequate.] 



4. KiDSTON, R. — Les Vegetaux Houillers recueillis dans le Hainault Beige. 



Pinakodendron Ohmanni, Weiss, pp. 166-172. PI. xxiv, figs. 1-11, 

 &c. (Mem. du Musee Roy. d'Hist. Nat. de Belgique, Bruxelles, 

 t. iv, 1909.) 



