164 



This research shows clearly that it would be dangerous to 

 base a comparison between Pittospoi^aceae and other Roscdes 

 upon the structure of the embryosac because in this respect 

 there is a great difference between the two species of Pittos- 

 porum examined. 



DESCRIPTION OF THE FIGURES. 



PLATE XXIII— XXVI. 



Magnification of figure 5 480; of all other figures 1200. 



Fig. 1 — 6 Plttosporum ramiflorum. 



Fig. I. Very young ovule of PUtosporum ramiflorum with an archespore showing 



chromosomes. 

 Fig. 2. Sporemothercell of P. ramiflorum surrounded by the nucellus and one 



integument. 

 Fig. 3. Tetrad of P. ramiflorum in which one cell-division is visible. 

 Fig. 4. Embryosac of P. ramiflorum which is still binucleated. 

 Fig. 5. An ovule of P. ramiflorum with a fullgrown embryosac in it. 

 Fig. 6. The upper-part of the embryosac of P. ramiflorum with an egg, two 



synergids and two polar nuclei, some degenerated nucellus-cells and a part of 



the integument. 



Fig. 7 — 11 Pitlosporum timorense. 



Fig. 7. Tetrad of Pitlosporum timorense. 



Fig. 8. Embryosac of P. timorense with one nucleus and two degenerated tetrads 



above it. 

 Fig. 9. Embryosac of P. timorense with egg, synergids, two polar nuclei and 



antipodes. 

 Fig. 10. Embryosac of P. timorense with endosperm-nuclei. 

 Fig. 11. Two sporemothercells of P. timorense after the first division ; the two 



sporeraothercells were separated by a wall. 



