Cupressineae , with special reference to Lihocedrus decitrrens. 283 
discharge from the microsporangium, Libocedrus agrees with the majority 
of other Cupressineae, but apparently differs from Juniperus and Cupressus , 
where, according to Strasburger (’92) and Coker (’04), there is no division 
of the microspore nucleus until some time after pollination. 
During the period of pollination the micropyle exudes a small globule 
of transparent liquid. The purpose of this is no doubt to catch the pollen 
more effectively, for an examination of the globule upon a slide under the 
microscope showed it to contain several pollen-grains. The same thing has 
been observed in other Conifers — especially in Taxus bacccita , where the 
globule of liquid is particularly obvious. It was observed more frequently 
during the early morning, before the heat of the day had time to cause 
evaporation. 
The pollen-grain of Libocedrus is — like that of other Cupressineae — very 
small. It contains but two cells, and in this regard resembles all other 
Conifers except the Abietineae and Podocarpeae. No trace of the survival 
of sterile prothallial cells was found. The single or first division which takes 
place, and which results in the organization of the generative and tube-nuclei, 
is the only division in the male gametophyte preceding that resulting in 
the formation of the body and stalk-nuclei. In view of more recent studies 
on the pollen, Coker’s statement, that ‘ In the absence of any sterile 
prothallial cells, Taxodium agrees with the Cupressineae and Taxus, and 
differs from all other Conifers and Cycads,’ is misleading ; for we now 
know that these prothallial cells are not of general occurrence among the 
Coniferales, but are probably confined to the Abietineae and Podocarpeae 
At the time of the shedding of the pollen in Libocedrus , the tube-nucleus 
is centrally situated, and is considerably larger than the generative nucleus. 
The latter was invariably found lying to one side near the spore-wall. 
Several spores find their way to the apex of the nucellus, and here 
retain their positions for three or four weeks without any further visible 
changes. Meantime the cells lining the upper part of the integument grow 
inwards, and gradually close the micropyle in essentially the same manner 
as they do in Sequoia and Ciyptomeria (Lawson, ’04). The next indication 
of the further germination of the spore was its enlargement to about twice 
or three times its original size, and the appearance of the pollen- tube. The 
latter at first pushes out over the top of the nucellus, but very soon begins 
its downward penetration into the nucellar tissue, without any indication 
whatever of branching. Very young pollen- tubes were observed early in 
May, which was just about a month after pollination. There are usually 
three or four pollen-tubes present, but as many as six have been observed 
penetrating the tissue of a single nucellus. The courses they follow diverge 
very little out of the straight lines between the original points of penetration 
and the archegonial chamber below. Their growth is accompanied by the 
usual breaking down and disorganization of the nucellar tissue through 
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