624 DR R. KIDSTON AND PROF. W. H. LANG ON OLD RED SANDSTONE PLANTS 
Fig. 4. The transverse section of a stem apex in fig. 2 ( b ). x 105. (Slide No. 2425.) 
Fig. 5. Longitudinal section of stem showing incompletely developed tissue with cell contents, x 33. 
(Slide No. 2426.) 
Fig. 6. Basal region of the sporangium shown in Part I, PI. IX, figs. 63 and 63 (a), ep., epidermis ; 
m.l., decayed middle layers of wall ; tap., tapetum. x 60. (Slide No. 2392.) 
Fig. 7. Apical region of the same sporangium. ep., epidermis ; tap., tapetum. x 60. (Slide 
No. 2392.) 
Fig. 8. Sporangium in transverse section, ep., epidermis; m.l., decayed middle layers of wall; tap., 
tapetum. x 14. (Slide No. 2427.) 
Fig. 9. Sporangium in obliquely transverse section full of spores, x 14. (Slide No. 2424.) 
Fig. 10. Obliquely longitudinal section of sporangium without tapetum and without specially thickened 
epidermal layer, the cavity partially filled with fully developed spores, x 14. (Slide No. 2423.) 
Fig. 11. Small sporangium in which the mass of spores is enclosed by a wall like the ordinary tissues 
of the stem. x 33. (Slide No. 2428.) 
Fig. 12. Spores in tetrads from the sporangium in fig. 11. x 105. (Slide No. 2428.) 
Fig. 13. Mature spores from the sporangium shown in fig. 9. x 160. (Slide No. 2424.) 
Plate II. 
Rhynia major, Kidston and Lang. 
Fig. 14. Transverse section of a moderately large and well-preserved stem, ep., epidermis; o.c., outer 
cortex; i.c., inner cortex; ph., phloem; x., xylem; a, interruption in outer cortex in relation to a stoma, 
x 20. (Slide No. 2429.) 
Fig. 15. Transverse section of one of the smallest stems met with, showing the relatively large stele, 
x 20. (Slide No. 2430.) 
Fig. 16. Transverse section of stele, photographed to show the phloem. x 33. (Slide No. 2431.) 
Fig. 16a. Central portion of specimen seen in fig. 16, photographed with different screen to show details 
of the xylem. x.o., outer xylem ; x.i., central xylem. x 60. (Slide No. 2431.) 
Fig. 17. Longitudinal section of stem with well-preserved stele, o.c., outer cortex ; i.c., inner cortex; 
ph., phloem ; x., xylem. x 20. (Slide No. 2429.) 
Fig. 18. Longitudinal section of stem, the inner cortex and phloem decayed, o.c., outer cortex interrupted 
at a beneath a stoma ; x., xylem. x 14. (Slide No. 2395.) 
Fig. 19. Transverse section of large stem showing the breaking down of the inner cortex as the result 
of decay, o.c., outer cortex; i.c., inner cortex; ph., phloem; x., xylem. x 20. (Slide No. 2398.) 
Plate III. 
Rhynia major, Kidston and Lang. 
Fig. 20. Longitudinal section of stele with the soft tissues preserved, i.c., inner cortex ; ph. phloem ; 
x., xylem. x 60. (Slide No. 2429.) 
Fig. 21. Group of stems compressed in the peat, the one at a showing two steles in preparation 
for dichotomous branching, x 14. (Slide No. 2432.) 
Fig. 22. Stele from a stem photographed to show the xylem. i.c., inner cortex ; ph., phloem ; x.o., 
outer xylem ; x.i., central xylem. x 60. (Slide No. 2432.) 
Fig. 23. Transverse section of a large decayed sporangium filled with spores. Only the thickened 
epidermis is preserved, and this is broken and overlapped at a. x 14. (Slide No. 2433.) 
Fig. 24. Transverse section of sporangium with well-preserved wall, ep., thickened epidermis; m.l., 
middle layers of wall; tap., tapetum; sp. spores. x 14. (Slide No. 2434.) 
Fig. 25. Portion of the silicified peat composed of decayed stems of Rhynia major with two sporangia 
of this species, x 7. (Slide No. 2435.) 
Fig. 26. Spores from sporangium in fig. 23. x 160. (Slide No. 2433.) 
