1904] COKER—SPORES OF CONIFERAE 209 
starch was found at this stage, but when the pollen was put in sugar 
solution it made its appearance in about two days. A sprouting 
grain that had been in sugar solution six days is shown in fig. 12. 
Here the prothallial cell and the generative cell are changed in posi- 
tion and the tube nucleus has moved down, and is surrounded by 
starch. One prothallial cell has been found in Ceratozamia, Zamia, 
and Cycas.? 
THE MEGASPORE AND EMBRYO SAC.—In the Cupressineae there is 
practically nothing known of the behavior of the megaspore mother- 
17 
: Fics. 13-17. Thuja orientalis; fig. 13, megaspore mother-cell surrounded 
4 money tissue, X 335; jig. 14, megaspore mother-cell during first division, 
595; fig. 15, tetrad of megaspores, X 525; fig. 16, the same, X 525; fig. 
'4, abnormal ovule with two sporongia, X 43. 
rm or of the origin of the megaspore. In Taxodium, which I con- 
tedkeg belonging to this group, the megaspore mother-cell divides 
jae — potential spores, the largest of which is functional. As to 
ac. ge of the group there is scarcely any literature that treats 
aes = STRASBURGER’ remarks that in Thuja the origin of the 
TYO sac is essentially as in Taxus. 
2 The li : . 
= literature on this point is cited in my paper on Taxodium. 
Angiospermen und die Gymnospermen. 1879. 
