1904] CURRENT LITERATURE 235 
The reduction division preceding the formation of pollen mother-cells occurs 
during the first week in December, Pollination occurs during the first week 
of January, each microspore containing tube and generative nuclei, with no 
trace of prothallial cells. The microspores remain in the micropyle three or 
four weeks before further germination, when tubes are put forth and pass in 
various directions, some between the integument and nucellus, others directly 
into the nucellus. No branching of tubes was found, as report N) 
At this time the division of the generative nucleus into stalk and prs pundes 
was observed, the latter becoming surrounded by a dense mass of cytoplasm 
invested by a membrane. e maturity of the body cell was obtained at 
various times between early in May tothe middle of June. The spindle 
organized for the formation of the male cells was found, but no trace of an 
organ suggesting a blepharoplast could be observed. 
Five or six megaspore mother-cells become differentiated rather deep in 
the nucellus, and each one divides twice (about March 1), but develops only 
two megaspores. The ten or twelve megaspores begin to germinate, but only 
two or three get beyond the first division and continue to elongate toward the 
chalaza, and one of these soon becomes dominant. Free nuclear division 
occurs in the two extremities of the embryo sac, and at the last division 
neighboring nuclei become connected by radiating fibrils, and cell plates 
are formed. The development of the endosperm takes about three months, 
archegonium initials appearing during the first week in June. 
Numerous archegonium initials become differentiated deep in the micro- 
pylar region of the prothallium, the neck cells being forced toward the 
periphery of the endosperm by the elongation of the central cells. Two neck 
cells were observed, confirming Arnoldi, though occasionally four were 
formed. The nucleus representing the ventral canal cell was also observed, 
which, in the absence of a cell plate and on account of its ephemeral exist- 
ence, may well have escaped the earlier observers. A remarkable feature in 
connection with the archegonia is that their necks are directed toward the 
nearest lying pollen tubes, which have taken up various positions before the 
archegonia are formed. 
Fertilization is unique in the fact that only the male nucleus, with a very 
small amount of cytoplasm, leaves the tube and enters the archegonium, the 
denucleated male cell retaining its form in the pollen tube. In fusion the two 
chromatin masses form a common network, and the male and female constit- 
uents become indistinguishable. As a rule, the two male cells fertilize two 
neighboring archegonia. The development of the embryo is also a decided 
departure from the ordinary early stages observed in conifers, in that there is 
no free nuclear division. The first division of the egg nucleus results in two 
walled cells, so large that they almost fill the egg. Subsequent divisions 
result in a row of five large cells, the lowest of which gives rise to the embryo, 
and the next above to the suspensor. In the first spindle. of the embryo the 
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