88 Gibson. — Anatomy of the genus Selaginetla , Spr. 
S, Martcnsii , Spr. 
Fig. 7. Longitudinal section through the growing-point of S. Martensii. X350. 
The initial cells of the ligule are shaded. 
Fig. 8. Longitudinal section through an almost mature ligule. The narrow 
sheathing cells, three in number in section, are followed by three glossopodial cell- 
rows ; the body of the ligule is composed of an irregularly arranged mass of densely 
granular cells, followed by the membranous terminal lamella, x 350. 
S. Braunii Bak. 
Fig. 9. Longitudinal median section of a very young ligule of S. Braunii. 
Four rows of initial cells are represented, x 350. 
Fig. 10. Longitudinal section of a slightly older ligule of the same. X350. 
Fig. 11. Transverse section of the base of a young ligule, taken just above the 
glossopodium. x 350. 
Fig. 12. Longitudinal section of an old ligule. The sheathing and glossopodial 
cells are arranged in four rows. X350. 
Fig. 13. Ligule of S. Martensii, Spr., isolated from its sheathing-cells. x6o. 
Fig. 14. Isolated ligule of S. grandis, Moore. x6o. 
Fig. 15. Isolated ligule of S. Vogelii , Spr. x6o. 
Fig. 16. Isolated ligule of S. erythropus , Spr. x 60. 
Fig. 17. Longitudinal median section through an old ligule of S. Helvetica , Lk. } 
showing the thick-walled sheathing cells and the enlargement of the vascular 
bundle of the leaf to form a tracheidal cup round the glossopodium. x 350. 
Fig. 18. Transverse section through the glossopodial region of an old ligule of 
S.Jlabellata, Spr. X350. 
Fig. 19. Longitudinal median section through the ligule and leaf-base of 
S. oregana , Eat. XI50. There are two rows of sheathing and of glossopodial 
cells, the entire ligule being depressed and almost hidden in an involution of the 
leaf-base. 
Fig. 20. Longitudinal median section of the base of a mature ligule of S. grandis, 
Moore, x 350. 
Fig. 21. Longitudinal median section of the ligule of S. laevigata , Bak. var. 
Lyallii , Spr., showing the enlarged tracheidal cup surrounding the base of the 
ligule. X150. 
