ON LEPIDOPHLOIOS SCOTTIL 453 



BIBLIOGRAPHY. 



Kidston, R. (1893), "On Lepidophloios, and on the British Species of that Genus," Trans. Roy. Soc. Edin., 



vol. xxxvii. pt. 3. 

 Scott, D. H. (1900), Studies in Fossil Botany, London, 1900. 



,, (1906), "The Present Position of Palaeozoic Botany," Progressus Rei Botanicx, 1907. 



Watson, D. M. S. (1907), "On a Confusion of two Species (Lepidodendron Harcourtii, Witham, and L. 



Hickii, sp. nov.) under Lepidodendron Harcourtii. Witham, in Williamson's XIX. Memoir; with a 



description of L. Hickii, sp. nov." 

 Williamson, W. C, "On the Organisation of the Fossil Plants of the Coal Measures," Phil. Trans., part ii. 



(1872); part iii. (1872); part xix. (1893). 



EXPLANATION OF PLATES. 



Figs. 1-14. Photomicrographs by A. G. Stenhouse, F.G.S., and the author. 

 Fig. 2a. Camera Lucida drawing by the author. 



Fig. 1. Transverse section of Lepidophloios Scottii. x = xylem ; ph. = phloem ; m.c. = middle cortex; 

 (i.e. = outer cortex ; pd. = periderm ; hr. = branch. Scott Collection 965. x 5. 



Fig. 2. Tranverse section of central xylem cylinder, p = pith ; I = central lamella ; t' = end of short 

 tracheide. Gordon Collection 176. x 36. 



Fig. 2a. Enlarged drawing of tracheides to show central lamella (I). 



Fig. 3. Longitudinal section of stem. x = xylem; m.c. = middle cortex; o.c. = outer cortex; pd. = 

 periderm. Gordon Collection 173. x 2. 



Fig. 4. Longitudinal section of xylem cylinder, l.t. = leaf-trace bundle ; t = tracheides of xylem (scalari- 

 forrnly thickened) ; p = pith. Gordon Collection 228. x 14. 



Fig. 5. Longitudinal section of xylem. t = tracheide (scalariformly thickened) ; t' = short tracheide 

 (reticulately thickened). Gordon Collection 223. x 36. 



Fig. 6. Longitudinal section through a branch, x = xylem of main stele ; x = xylem of branch ; p = pith 

 cells growing out through gap. Gordon Collection 228. x 36. 



Fig. 7. Transverse section of leaf-bases, showing keeled and unkeeled region of leaf-bases, but sloping 

 out from the stem. Gordon Collection 216. x 2. 



Fig. 8. Transverse section of stem with leaf-bases attached. a = stigmarian rootlet; ox. = outer 

 cortex; pd. I a,nd.pd. 2 = layers of periderm; l.b. = leaf -base. Gordon Collection 152. x 3. 



Fig. 9. Transverse section of leaf-base. v. b. = vascular bundle ; par. = parichnos. Gordon Collection 

 215. x 12. 



Fig 10. Longitudinal radial section of leaf-base. l.s. = leaf -scar ; c.d. — concave depression ; Ig.c. = ligular 

 canal ; Ig.p. = ligular pit. Gordon Collection 223. x 12. 



Fig. 11. Transverse section of leaf-trace bundle in inner part of outer cortex. m,c. = middle cortex 

 coming out with the bundle ; v.b. = vascular bundle. Gordon Collection 196. x 36. 



Fig. 12. Transverse sections of leaf-trace bundles in the periderm, par. — parichnos. Gordon Collection 

 194. x 12. 



Fig. 13. Part of fig 12. x = xylem ; b.s. = bundle sheath ; par. = parichnos. x 48. 



Fig. 14. Longitudinal radial section of leaf-base. l.s. = leaf -scar ; Ig. =ligule; par. = parichnos ; c.d. = 

 concave depression. Gordon Collection 173. x 12. 



