Cupressineae, with special reference to Libocedrus decurrens . 285 
body-cell as giving rise to a complex of cells. Realizing the importance of 
such a condition, I have made a careful study of the pollen-tube in two 
other species of Cupressns , and the conditions found there were almost 
identical with those described above for Libocedrus . In both species studied 
I found that two male cells of equal size were organized, and that the stalk- 
and tube-nuclei in addition to these constituted the entire nuclear structures 
of the pollen-tube. The two male cells were also followed through the 
fertilization stages. I am therefore compelled to regard the condition de- 
scribed by Juel in Cupressus Goweniana as simply an interesting abnormality. 
In addition to the two species of Cupressus which I have examined, the normal 
condition of two male cells of equal size occurs in Taxodium , Cryptomeria , 
Juniperus , Thuja , and Chamaecyparis. The only other Conifer outside of 
the Cupressineae in which two distinct equal male cells have been observed 
is Sequoia (Shaw, ’96 ; Lawson, ’04). In all other Conifers of which we 
have record the male cells are either unequal in size ( Taxus , Belajeff, ’93 ; 
Podocarpus , Coker, ’02 ; Torreya taxifolia , Coulter and Land, ’05), or they 
are represented only by nuclei as in the Abietineae (Dixon (’94), 
Blackman (’98), Coulter and Chamberlain (’ 01 ), Ferguson (’ 01 )) and in 
Cephalotaxus (Lawson, ’07). 
As shown in Fig. 7 , the male cells become packed with starch grains, 
and in this respect resemble other members of the Cupressineae. As soon 
as the male cells are formed the contents of the pollen-tube are discharged 
into the archegonial chamber. The pollen-tube itself apparently does not 
carry the male cells into the archegonium. as it does in the Abietineae and 
some other Conifers, but its function evidently ceases when the archegonial 
chamber has been reached and its contents discharged. As I shall point 
out later, the archegonia throughout the Cupressineae are arranged in 
a single group with a common layer of jacket-cells, and with their necks 
opening into a common cavity or chamber. It is into this common chamber 
that the contents of the various pollen-tubes are discharged. As the arche- 
gonia are numerous, their arrangement in a single group makes it possible 
and easy for each male cell to function, so that the contents of each pollen- 
tube may accomplish the fertilization of two separate archegonia. These 
conditions seem to offer a fair explanation why one of the male cells is not 
dwarfed and functionless as it is in many other Coniferales. 
The history of the male gametophyte of L ibocedrus resembles that of 
Thuja probably more closely than any other of the Cupressineae. It agrees 
in all essential points with the account given by Land (’ 02 ) of Thuja occi- 
dentalism and also with my own observations on Thuja orientalis. The 
mature pollen of the latter species has but two nuclei — the generative and 
tube. The pollen-tubes develop and penetrate the nucellar tissue in identi- 
cally the same fashion as they do in Libocedrtis. PI. XXIV, Fig. 1 shows 
a young pollen-tube, and Fig. 2 shows at least four of them at a later stage. 
X 2 
