3 
Embryo of Cephalotaxus drupctcea. 
of the ventral canal-cell, and fertilization, a rapid fixation is quite necessary. 
Better results were always obtained when the material was placed in the 
killing fluid as soon as possible after being detached from the tree. For 
many stages it is even desirable to carry on the dissections while the 
material is submerged in the fixing fluid. 
The ordinary cytological methods were employed, details of which 
have already been published (Lawson, ’04). We need only add that 
Flemming’s weak solution and the chrom-acetic mixture gave the most 
satisfactory results as fixing reagents. The triple combination, safranin, 
gentian violet, and orange G. was used for staining. 
The Male Gametophyte. 
The first collection of the microsporangia was made on March i, 
before the megasporangia were visible. From then on to the time of 
pollination collections were made almost daily. The microspores from the 
early collections contained a single large central nucleus and a large 
quantity of starch grains. The spore at this time also showed a well- 
developed exine. Fig. i represents a cross-section of a young microspore 
just before its first division. Sections of the sporangia taken a day or two 
before the pollen was shed showed two distinct nuclei in each microspore, 
although I was unable to find the spindle showing the actual division of the 
first nucleus. One of these nuclei was larger than the other and more 
centrally located. The former is undoubtedly the tube nucleus, while the 
history of the smaller one proved it to be the generative nucleus. From 
the observations of Strasburger (’92) and Coker (’04) it appears that in 
Taxus , Juniperus , and Cupressus there is no division of the microspores 
during their confinement within the sporangium, while in the Abietineae 
and in Chamaecapyris , Cryptomeria , TJmja , Sequoia , Podocarpus , and 
Cephalotaxus the microspores divide before they are shed. 
In Cephalotaxus drupacea the first division of the microspore takes 
place at least a day or two before pollination. Fig. 2 represents a section 
of a pollen-grain at this time. It will be observed that the starch grains, 
which were formerly present in abundance, have entirely disappeared, and 
that there is an indication of a delicate membrane separating the two 
nuclei. In view of the importance of these early stages in the history of 
the male gametophyte, and especially in view of the fact that Cephalotaxus 
is regarded by many botanists as a primitive type of Conifer, a very careful 
search was made for any evidence of the survival of sterile prothallial cells 
as found in the Cycads, Ginkgo , and in the Abietineae, but no trace of such 
vestigial structures were found. There were but two nuclei present, and 
a careful study has convinced me that the division which gives rise to them 
(i. e. the generative and tube nuclei) is the only division in the male 
gametophyte which precedes the organization of the body and stalk 
