626 DR R. KIDSTON AND PROF. W. H. LANG ON OLD RED SANDSTONE PLANTS 
Fig. 41. Longitudinal section of stem about 5 mm. above its origin from a rhizome, ep., epidermis ; 
e., cortex with indications of outer and inner zones ; ph., phloem ; x., xylem. x 33. (Slide No. 2440.) 
Fig. 42. Transverse section of stem with stele just divided in preparation for dichotomy, cut., cuticle ; 
c., perished cortex; ph., well-preserved phloem; x,, xylem. x 33. (Slide No. 2446.) 
Fig. 43. One of the steles in fig. 42 more highly magnified, pli., phloem ; x.o., outer xylem ; x.i., central 
xylem. x 105. (Slide No. 2446.) 
Fig. 44. Small stem with relatively large stele. x 20. (Slide No. 2449.) 
Fig. 45. Stele of stem in fig. 44. x.o., outer xylem ; x.i., central xylem partially broken down, x 60. 
(Slide No. 2449.) 
Fig. 46. Another large stele with broken-down central xylem. ph., phloem ; x.o., outer xylem ; x.i., 
position of central xylem. x 33. (Slide No. 2450.) 
Fig. 47. Transverse section of stem-stele close to the rhizome, x.o., outer xylem; x.i., central xylem. 
x 60. (Slide No. 2447.) 
Fig. 48. Transverse section of large stele, x.o., outer xylem ; x.i., perished central xylem. x 60. (Slide 
No. 2447.) 
Fig. 49. Longitudinal section of xylem of stem-stele showing the continuous outer xylem (a;.o.) and the 
central xylem (x.i.) interrupted by breaks. x 60. (Slide No. 2441.) 
Plate VIII. 
Hornea Lignieri, Kidston and Lang. 
Fig. 50. Transverse section of stele near its origin from the rhizome, ph., phloem ; x.o., outer xylem ; 
x.i., central xylem. x210. (Slide No. 2447.) 
Fig. 51. Portion of the stele shown in fig. 47. ph., phloem; x.o., outer xylem; x.i., central xylem. 
x 210. (Slide No. 2447.) 
Figs. 52, 53. Tracheides in longitudinal section showing the fine irregularly spiral or reticulate thickening, 
x 210. Fig. 52 (Slide No. 2452); Fig. 53 (Slide No. 2451). 
Fig. 54. Short tracheides from the basal region of a stele showing the fine irregularly spiral or reticulate 
thickening, x 210. (Slide No. 2442.) 
Fig. 55. Stele showing dichotomy, x 60. (Slide No. 2442.) 
Fig. 56. Small stem with stele showing dichotomy, x 20. (Slide No. 2452.) 
Fig. 57. Small stem a showing dichotomously divided stele. x 20. (Slide No. 2453.) 
Plate IX. 
Hornea Lignieri, Kidston and Lang. 
Fig. 58. Portion of peat containing, besides more or less decayed stems of Hornea, two slender stems 
terminating in well-preserved sporangia cut in accurate longitudinal section. The sporangium to the left 
is bifurcate, that to the right is simple. A portion of the stele (st.) is seen in the stalk of each, x 14. 
(Slide No. 2454.) 
Fig. 59. Imperfect sporangium in longitudinal section showing flattened top. w., wall; sp., spores; 
col., columella. x 20. (Slide No. 2424.) 
Fig. 60. Broad divided sporangium terminating a stalk with two steles (st.). w., wall ; sp., spores ; col, 
columella, x 20. (Slide No. 2456.) 
Fig. 6 1 . Portion of peat with spores of Hornea distributed through it, and containing on the left a small 
stem (a) and on the right an obliquely- cut sporangium (b) showing the characteristic stele of Hornea. x 14. 
(Slide No. 2455.) 
Fig. 62. Oblique section of the base of a sporangium showing the continuity of the tissue of the 
columella with the phloem of the stele, tv., wall ; sp., spores ; col., columella ; ph., phloem ; x., xylem. 
x 60. (Slide No. 2456.) 
Fig. 63. Transverse section of a large partially divided sporangium with a single cavity, but the columella 
