230 



STUDIES IN FOSSIL BOTANY 



The most remarkable point, however, which they 

 observed is, that in traversing the phelloderm the leaf- 

 trace divides into two ; in the leaf-base the two xylem- 

 strands are wide apart. 



In 1879 Renault described, under the name of 

 Sigillariopsis Decaisnei} a small stem, with leaves 

 attached, from the Permian of Autun ; the stem 

 resembles that of Sigillaria Menardi in structure, but 

 the wood contains pitted as well as scalariform 



Fig. 95. — Sigillariopsis sulcata. Transverse section of leaf. v. It., the xylem-groups of 

 the double vascular bundle ; /, lacuna, representing secretory tissue ; t, t, transfusion- 

 tissue, forming a horse-shoe, surrounding the double bundle, but open above ; p.t., 

 palisade tissue on the upper side and flanks of the leaf ; f,f, stomatiferous furrows. 

 X 22. S. Coll. 2272. R. S. 



tracheides ; the leaf is traversed by two parallel 

 vascular bundles, which only fuse towards the tip. 

 These characters are altogether exceptional among 

 Lycopods, but in other respects the structure is quite 

 of the Lycopodiaceous type. Leaves occur in the 

 nodules of the British Coal-measures which agree with 

 those of Renault's plant in possessing two distinct 

 vascular bundles, though presenting some specific 



1 Structure comparte de quelques Tiges de la Flore Carbonifere, Paris, 

 1879, P- 2/°- 



