24 WATSON, Two Species of Lepidodendroii Harcourtii. 



DESCRIPTION OF PLATES. 

 Figs, i — 5. Microphotographs by the author. 



Figs. 6 — 9 and 11. Camera lucida drawings by Miss. K. H. 



Coward, B.Sc. 

 Fig. 10. Camera lucida drawing by the author. 



Plate I. 

 Fig. 1. Transverse section of a small stem of L. Hickii x (n). 

 The pith with dividing walls in the cells is well shewn. 

 It is surrounded by the ring of wood, the even contour of 

 which is very characteristic of the species. 



Numerous leaf traces are seen in the ill-preserved belt of 

 parenchyma surrounding the wood. 



In the south of the illustration is seen a stelar branch 

 supplying a " Halonial " tubercle. 



A 144. D. Watson collection. 



Fig. 2. Transverse section of a rather larger branch of L. Hickii 

 x(n). 



In the S. and S.E. the "zone rayonnee" of the middle 

 cortex is well seen. 



The piece of xylem ring on the E. is becoming detached 

 to form a branch to a Halonial tubercle. 

 A 170. I). Watson collection. 



Fig. 3. Longitudinal section of external portion of the wood of 

 a branch of L. Hickii, shewing origin of a leaf trace, 

 x (190). 



The bottom of the figure is occupied by the large 

 scalariform tracheids of the metaxylem. 



The leaf trace passes out to the N.E. corner of the 

 figure. 



A 201 F. D. Watson collection. 



