336 BOTANICAL GAZETTE [May 
Fic. 6. An older ovule showing the primary tapetal cell (7) and primary 
sporogenous cell. X 1300. 
7, Ovule with primary sporogenous cell and two tapetal cells. x 
1300. 
Fic. 8. Ovule with two tapetal cells and two cells derived from division 
of the primary sporogenous cell. X 1300. 
Fic. 9. Apex of nucellus with four mother cells. X 1300. 
Fic. 10. Ovule showing primary sporogenous cell elongating. X ! 
Fic. 11. Ovule with elongated primary sporogenous cell still mndivded 
Mm 825. 
Fic 12. First division of the primary sporogenous cell. X a 
Fic. 13. Second division in the megaspore series. X I 
Figs. 14 and 15. Apex of nucellus with four seas mother cells. 
25. 
Figs. 16-19. Irregular deltnosmeeie of the megaspore mother cells 
X 825. 
Fic. 20. Mitotic figure of first division of ac primary sporogenots 
cell; cytoplasmic radiations about one pole. 200 
IG. 21. Synapsis phase of the nucleus of the elongated poe. 
enous cell. X 2000. 
Figs. 22 and 23. The ad and the lower nucleus, 
78, both in synapsis. x 2 
Fig. 24. Apex of the oy with embryo sac after com 
nuclear division. 1300 : 825 
Fic. 25. The same ‘ee completion of second nuclear division. X 7 
Fic. 26. The same after completion of third nuclear division. siete oe 
Fic. 27. Lower end of an embryo-sac showing the three sien wi 
fusion of the polar nuclei. X 1300. 
Fig. 28. Embryo sac ready for fertilization. X 825- 
Fic. 29: Apex of the embryo sac with pollen ihe 
and oosphere. X 1300. 
Fic. 30. Part of cross section of anther; ¢, the tapetum. ae 
tapetum a layer of disorganized cells may be seen. X se in the pro 
FiG. 31. A single rounded pollen mother cell with its nucleus ! 
phase'stage. x 1300. ig. 3? 
Figs. 32-36. Stages in the divisions of the pollen san 2 an 
respectively, of fig: 
pletion of first 
striated synergids, 
ide the 
shows the chromosomes in the equatorial plate of the first igo: the 
_ the equatorial plate of the second mitosis. /7gs. 774 and 35% 
others X 1300. 
PLATE XX. 
on of sone = (g ‘ 
Fic. 38. A microspore ‘showing first organizati 
Zt 
In this and the following figures the tube nucleus is denote by 
