XVI] 



SIGILLARIA 



225 



The aerial shoots of this species are occasionally branched 

 dichotomously\ the apical portions bearing short crowded leaves^; 

 the surface of the bark is either completely covered with con- 

 tiguous leaf-scars without definite leaf-cushions or with projecting 

 cushions forming a narrow sloping surface surrounding each 



Fig. 203. 



Sigillaria Brardi Brongn. (J nat. size). From a photograph of a 

 specimen in Dr Kidston's collection, from the Upper Transition 

 Series of Staffordshire. Published by Kidston (02) PI. lix. fig. 1. 



leaf-scar. Other parts of the plant may possess cushions similar 

 in their kite-shaped form to those of Lepidodendron, but without 

 a median vertical groove, or the leaf-scars may be spirally disposed 

 at varying distances apart on a comparatively smooth and longi- 

 tudinally wrinkled bark. The species exhibits striking instances 

 of a transition between the Favularian, Clathrarian, and Leioder- 

 marian forms of stems. The leaf-scars, which are hexagonal in 

 1 Renault (96) A. PI. xxxv. ; ZeiUer (06) PI. xlii. ^ Grand'Eury (90) A. 



