40 



Fip:. 11. Section in tlie same direction of the reo-nlar cell 

 rows of the inner tissue of the root, mounted in 

 glj'cerine jelly. x 1075. 



Pi-ate IV^. : Histology of the Shoot. 



Fig. 12. A central cell from the longitudinal section of 

 an old shoot, stained with hopmatoxylin, 

 mounted in glycerine jf'Hy. Tlu' middle 

 lamella, the darker jwrtion of the cell wall, 

 which lias not swollen up, and the lighter and 

 stratified inner cell wall, which has swollen up, 

 may be distinguished. x 1075. 



Fig. 1-"). Large pit between two central cells in optical 

 section ; on the left the same in end view. 

 Mounted in glycerine jelly. x about -'iOOO. 



Fig. 14. The apical (smaller) and next inner cell of an 

 assimilating cell row. The former has a 

 smaller rbodoplastid than the latter. Fresh 

 material. x about 4000. 



Fig. 15. Transverse section across an inner assimilating 

 cell. The rbodoplastid lines the wall. Fresh 

 material. x about 4000. 



Fig. 10. The much-divided rbodoplastid of an inner 

 collecting cell. Starch is being formed here 

 and there. Fresh material. x about 4000. 



I'^ig. 17. Leucoplastid from a conducting cell. Fresh 

 material. x about oOOO. 



Fig. IS. Starch grain, seen from its broadest (a) and iis 

 narrowest side (b). Examined in iodine and 

 glycerine. x about 3000. 



Pl.\te v.: The Xemathecifm. 

 Fig. 19. Habit of a plant bearing nemathecia. x 2. 



