100 BOTANICAL GAZETTE [AUGUST a 
Fic. 5.—Second prothallial cell cut off, the first degenerating. 950. 
Fic. 6.—Spindle for generative cell. 950. 
Fic. 7.—Tube nucleus, generative cell, and prothallial cells. 950. 
Fics. 8, 9.—Generative cell dividin we X950 
Fic. 1o.—Mature pollen grain 
Fics. 11, 12.—First prothallial call adie and the second divided. X950. | 
Fic. 13.—Mature grain, showing a part of the stalk cell on each side of the 
body cell. X50. 
Fic. 14.—Nuclei becoming free. X50. 
Fic. 15.—Diagram of vertical section through dotted line in fig. 16 
Fic. 16.—Diagram of horizontal section through dotted line xy of fig. 15, 
showing form of stalk cell. 
1G. 17.—Horizontal section, showing stalk and second prothallial cells and 
‘tube and body nuclei. Xgs50. 
Fic. 18.—Outline drawing of Dioon.—From CHAMBERL 
Fic. 19.—Body cell in the grain; stalk, tube, and septal nuclei in the 
wef 
440. 
Fries 20.—Body cell divided, forming two unequal male cells. 440. 3 
Fic. 21.—Longitudinal section of ovule and bract; pollen grains on the 
nucellus. 45. 
Fic. 22.—Young stage of the arillus; detail of fig. 21. X44 
Fic. 23.—Two-nucleate stage of female gametophyte; Sita = fig. 21. X40. 
Fic. 24.—Young archegonium, showing primary neck and central cells. 
Fic. 25. —Young archegonium; primary neck cell divided. X 440. 
ge. 440. 
Fic. 28.—Stretching of adjacent jacket cells under pressure of the pollen 
tube; body cell and central nucleus not yet divided. 440. 
Fic. 29.—Eight-celled neck. 440. 
and v 
IG. 30.—Egg and ven canal nucleus. 440. a 
Fic. 31.—Endosperm cells and megaspore membrane; January 28. X950- 
Fic. 32.—Egg ready for fertilization; four-celled neck and jacket membrane . 
male aie stalk, prothallial, and tube nuclei. 440. 
Fic. 33.—Effect of pollen tube on an Sagem the membrane intact. 
: : : 
Fic. 36.—Female gametophyte. X 45. 
Fic. 37.—Megaspore membrane and archegonial cavities. *449- 
ata: 
