

782 DR R. KIDSTON AND PROF. W. H. LANG ON OLD RED SANDSTONE PLANTS 



Fig. 16. Tangential section showing the isodiametric epidermal cells of a rhizome in surface view. 

 /•A., rhizoids. x 60. (Slide No. 2396.) 



Fig. 17. Two rhizomes in the peat in transverse section. Further description in text. x 14. (Slide 

 No. 2396.) 



Fig. 18. Section through a rhizoid-bearing bulge of another rhizome showing the long non-septate 

 rhizoids extending downward into the peat, rh., rhizoids. x 28. (Slide No. 2411.) 



Fig. 19. Transverse section of rhizome. < 60. ep., epidermis; o.c, outer cortex; i.e., inner cortex ; 

 />li.., phloem ; x., xylem. (Slide No. 2396.) 



Plate V. 



Fig. 20. Section through chert showing cylindrical aerial stems in an almost pure silicious matrix free 

 from foreign vegetable matter. x 9. (Slide No. 2408.) 



Figs. 21-25. Transverse sections of aerial stems of different diameters. x 20. The various regions of 

 the stem distinguished by lettering in figs. 21 and 23 can also be recognised in the other figures, ep., 

 epidermis; o.c, outer cortex; i.e., inner cortex; ph., phloem; x., xylem. Fig. 21 (Slide No. 2398). Fig. 22 

 (Slide No. 2398). Fig. 23 (Slide No. 2397). Fig. 24 (Slide No. 2399). Fig. 25 (Slide No. 2416). 



Fig. 26. Portion of a longitudinal section of an aerial stem. ep., epidermis; o.c, outer cortex; 

 i.e., inner cortex; ph., phloem; x., xylem; pr., small projection. x 20. (Slide No. 2390.) 



Fig. 27. Transverse section of an aerial stem showing three projections. pr., projections. x 20. 

 (Slide No. 2406.) 



Figs. 28-29. Transverse sections of two stems showing small projections bearing rhizoids. pr., pro- 

 jections ; rh., rhizoids. x 20. (Slide No. 2389.) 



Fig. 30. Transverse section of an aerial stem showing the stele dividing preparatory to dichotomous 

 branching. x 20. (Slide No. 2392.) 



Plate VI. 



Fig. 31. Epidermis in surface view showing the form of the cells and the dark median line. x 60. 

 (Slide No. 2390.) 



Fig. 32. Stoma with surrounding epidermal cells in surface view; median line absent. Of. fig. 31. 

 x 160. (Slide No. 2394.) 



Fig. 33. Stoma in transverse section showing the two guard cells and the pore. x 160. (Slide 

 No. 2408.) 



Fig. 34. Transverse section of the epidermis and the underlying tissues in the neighbourhood of a 

 stoma, st., stoma; ep., epidermis; o.c, outer cortex interrupted beneath stoma; i.e., inner cortex extending 

 outwards to beneath stoma. x 160. (Slide No. 2405.) 



Fig. 35. Epidermis and underlying tissues in two adjacent stems. . ep., epidermis ; o.c, outer cortex ; 

 i.e., inner cortex. x 60. (Slide No. 2405.) 



Fig. 35. Transverse section showing the cuticular ridges of the epidermal cells. Cf. fig. 31. x 60. 

 (Slide No. 2389.) 



Fig. 37. Longitudinal section through the epidermis and outer cortex in the region of a stoma (st.). The 

 inner cortex which filled the interruption in the outer cortex has decayed, x 60. (Slide No. 2395.) 



Fig. 38. Transverse section showing the rounded cells and intercellular spaces of the inner cortex. 

 x60. (Slide No. 2398.) 



Fig. 39. Transverse section of inner cortex showing the cell contents partially preserved. x 160. 

 (Slide No. 2395.) 



Fig. 40. Transverse section of an aerial stem, ep., epidermis ; o.c, outer cortex, not well marked ; i.e., 

 inner cortex with large intercellular spaces ; ph., phloem ; x., xylem. x 60. (Slide No. 2397.) 



Plate VII. 



Fig. 41- Transverse section of stem with well-marked stele, ph., phloem; x., xylem. x 60. (Slide 

 No. 2392.) 



Fig. 42. Portion of longitudinal section of stem shown in fig. 26 more highly magnified, ep., epidermis ; 

 o.c, outer cortex ; i.e., inner cortex ; ph., phloem ; x., xylem. x 60. (Slide No. 2390.) 



