148 Gager.—Asclepias Cornuti , Decaisne . 
bodies. The nucleoli have each one large vacuole. No. 14 had already given off 
one fragment . x 1225. 
Fig. 15. Nucleus of primary pollinium-cell showing six nucleoli. The larger 
one suggests a possible origin of the wart-like bodies, x 1225. 
Fig. 16. Nucleus of primary pollinium-cell showing early spireme. Two 
vacuoles in the nucleolus, x 1225. 
Fig. 17. First division of the primary pollinium-cells. x 450. 
Fig. 17 a. Detail of first division of primary pollinium- cell, showing the reduced 
number (twelve) of chromosomes, x 1525. 
Fig. 18. Later stage in first division of the primary pollinium-cell. Cell-plate 
and kinoplasmic radiations from the daughter-nuclei, x 450. 
Fig. 19. Nucleus after completion of first division of primary pollinium-cell. 
x 1225. 
Fig. 20. Still later stage than Fig. 19 in first division of primary pollinium-cell. 
Cell-plate complete ; daughter-nuclei moving to centre of daughter-cells, x 450. 
Fig. 21. Second division of primary pollinium-cell. x 450. 
Fig. 2i«. Detail of second division of primary pollinium-cell, showing the 
reduced number of chromosomes, twelve at the lower pole, eleven at the upper, 
x 1525. 
Fig. 22. Second division of primary pollinium-cell, cell-plate stage. Kino- 
plasmic radiations from daughter-nuclei, x 450. 
Fig. 23. Second division of primary pollinium-cell complete, showing the four 
radially arranged tetrads. x 450. 
Fig, 24. Four tetrads from the same mother-cell, rounded, showing the delicate 
inner membrane and the early appearance of the rod-shaped bodies, x 450. 
Fig. 25. Young microspore showing further development of rod-shaped bodies, 
x 450- 
Fig. 26. Young pollinium-cell. The nucleus appears affixed to the cell- wall 
previous to the first division. The inner cell membrane and the rod-shaped bodies 
are prominent, x 1225. 
Fig. 27. Fragmentation of nucleolus before first division of the pollinium-cell. 
Cf. Fig. 15. x 1225. 
Figs. 28-31. The first division of the pollinium-cell. x 1225. 
Fig. 32. Division figure in the formation of the two sperm-cells, x 1225. 
Fig. 33. Division complete, forming the two sperm-cells, x 858. 
Fig. 34. Cross-section of pollinium. The pollinium-cells at the left have begun 
to germinate, x 85. 
Fig. 35. Germination of mature pollinium-cell. x 450. 
Fig. 36. Fertilization-tube germinated on the stigma. The tube-nucleus is 
in advance of the two sperm-cells, x 858. 
Fig. 37. Fertilization-tube about to enter the micropyle. The two sperm-cells 
have passed the tube-nucleus. Two synergids and oosphere in the embryo-sac. 
X 45°- 
