222 STUDIES IN FOSSIL BOTANY 



short thin-walled cells of greater diameter. As the 

 fibrous bands, which no doubt had a mechanical 



\, 



Fig. 92. — A and B, Sigillaria spinnlosa, A. Tangential section of outer cortex, showing 

 leaf-trace, with the parichnos (pa) on either side. In the leaf-trace ; x, primary 

 xylem ; below this the secondary xylem (tr) and phloem, then a sclerenchymatous 

 strand ; s, sheath of bundle. Magnified. B. Leaf, showing the lower surface, and 

 the scar (sc) at base ; on the scar the prints of the bundle and parichnos are seen. 

 m, midrib of leaf; g, one of the stomatiferous furrows. Nat. size. C. £. latifoiia. 

 Transverse section of leaf, x, xylem ; s, sclerenchyma ; er, trans fusion -tissue ; g f 

 stomatiferous furrows, lined with hairs. Magnified. All after Renault. 



function, fuse with each other in every direction, they 

 form a network, whether seen in tranverse or tangential 



