Dixon — On the Vegetative Organs of Vanda teres. 457 



Fig. 8. — Central portion of a transverse section of the cylindrical leaf 

 of Dendrohium terettfolium, containing the axial passage, 

 lined with small epidermal cells, x 160. 



Fig. 9. — Epidennal cells seen in transverse section of the leaf of 

 V. teres. The upper portion shows the structure of a 

 stoma, with the collar of cuticle standing up round it ; 

 in the lower is seen the dome-shaped outer wall, with 

 its central knob of the cells of the leaf epidermis. 

 X 160. 



Fig. 10. — A cell from a transverse section of the cortex of a root of 

 V. teres, showing the fibrous thickenings arching over 

 the intercellular passages, x 125. 



Fig. 11. — Velamen and exodermis of V. teres, seen in transverse 

 section of the root, x 160. 



Fig. 12. — Similar to fig. 8. Central portion of a transverse section, 

 taken near the base of the leaf of Dendrohium tereti- 

 folium, showing the axial passage triangular in cross- 

 section. X 160. 



Plate XIII. 



Fig. 13. — Cells containing siHcious bodies on the outside of the 

 sclerenchymatous bundle-sheath of a fully developed 

 leaf, from a radial section. V. teres, x 210. 



Fig. 14. — Similar to fig. 13, but from a younger leaf. In some of the 

 cells containing the silicioUs bodies a nucleus can be 

 seen, x 210. 



Figs. 15 & 16. — Transverse sections of a bundle ending blindly in the 

 lignified parenchymatous tissue of the stem of V. teres. 

 Fig. 15 is drawn from the last section of a series in 

 which it was traceable. Fig. 15 x 280, and fig. 

 16 X 240. 



Fig, 17. — Radial section of an immature leaf, showing the cells 

 which give rise to the silicious bodies on the outside of 

 the bundle-sheath of V. teres. The white mass beside 

 the nucleus of some of the cells is the beginning of the 

 silicious body. 



Fig. 18. — Similar to fig. 17. A later stage. 



