126 BOTANICAL GAZETTE [ FEBRUA 
the large size and prominent chromatin network which marks approwt 
ing division. The tapetum, now much compressed by the growingspr 
mother cells, is more sharply marked than in the January preparation 
Collections of May 4 had the macrospore developed almost to tt 
formation of archegonia. 
Pinus Banks1ana Lambert.— About a dozen macrosporangia, 0 
lected May 14, showed the macrospore mother cell, but materid 
collected in a neighboring locality two weeks earlier showed an eile 
sperm of several cells. Mitotic figures are very frequent in all 
these spring collections, so that it is very possible that the mactoy 
rangia also pass the winter in the spore mother cell stage. 
Cupressus Lawson1aANa Murray.— October microsporangia shore 
pretty uniformly the condition represented in jig. 5. The nucle | 
the spore mother cells usually have a single prominent nucleolus whe 
reached the spore mother cell stage in October (fig. 6), but th 
were still rather small in comparison with the size of the cell. . 
tapetum is sharply differentiated, and its cells show no tendeng}! 
plasmolyze like the other cells of the sporangium wall. The mae 
sporangia were not studied. 
TRILLIUM. — Miss Arma Smith? found microsporangia of : 
lium in the spore mother cell stage in buds taken from beneath ® 
frozen soil on April 5. In one case the mother cells were A 
going division. This suggests that cell division, which I feel s 
does not take place under our usual winter conditions, may be eee 
while the temperature is still near the freezing point. 
a 
studying the earlier stages of the embryo sac. Some of mj 
collected September 27 was young enough for the stu 
development, while the largest buds showed microsporangi® 
pollen mother cell stage. Another collection taken th 
while the ground was still frozen had pollen fully formed 38 
*Abortive flower buds of Trillium. Bot. GAz. 22: 402. 1896. 
Contributions to the embryology of the Ranunculace®. 
95. 
Bot. G 
298. 18 : 
