2 IO 
Agnes Robertson. 
nucleus, suggesting, though to a less degree, the curious structure 
found by Miss Ferguson 1 in the cytoplasm of the body-cell of Pinus 
before division of the nucleus. 1 am sorry to say that I have not 
succeeded in observing the division of the body-cell nucleus. Fig. 
16 shews a body-cell enclosing two sperm-nuclei. These two nuclei 
seem never to be surrounded by separate masses of cytoplasm, 
agreeing in this respect with Pinus. 1 Fig. 17 shews one male 
nucleus in contact with the neck of an archegonium while the 
second is some distance behind. One vegetative nucleus is in 
contact with the body-cell. I believe that only one of the two male 
nuclei is functional, for I have invariably found a separate pollen- 
tube corresponding to each fertilised egg. So far as I have observed 
the functional nucleus is no larger than the other. In the equality 
of the sperm-nuclei Torreya agrees with Cephalotaxus as described 
by Arnoldi, 2 but differs from Taxus 3 as represented in BelajefT’s 
well-known figure. 
VI. —Fertilisation. 
The passage of the functional male nucleus into the arche¬ 
gonium is shewn in Fig. 18, which is drawn from an ovule gathered 
on August 31st. The second male nucleus and the rear half of the 
body-cell are left in the pollen-tube. A hand section, cut by Mrs. 
Tansley, of an ovule collected on September 17th, 1902, shews a 
similar stage. In Fig. 19 the male nucleus is actually in contact 
with the egg-nucleus whose membrane is pressed in like a collapsing 
india-rubber ball. This peculiar method of union of the male and 
female nuclei was first recorded by Blackman 4 for Pinus, and has 
since been demonstrated in various other Gymnosperms. It appears 
usual in Conifers for the male nucleus to slip from its protoplasmic 
sheath as it approaches the egg-nucleus, and leave it behind near 
the point of entrance. In Sequoia 5 the male nucleus even enters 
the egg naked, shedding its cytoplasm outside. Coker 0 in his paper 
1 M. C. Ferguson. “ Development of the Pollen-Tube and the 
Division of the Generative Nucleus in Pines.” Annals of 
Botany. Vol. XV., 1901, p. 194. 
2 W. Arnoldi. “ Embryogenie von Cephalotaxus Fortunei.” 
Flora 87, 1900, p. 46. 
3 W. C. Belajeff. “ Zur Lehre von dem Pollenschlauche der 
Gynmospermen.” Ber. der deutsch. Bot. Gesellschaft. Bd. 
IX., 1891, p. 280, PI. XVIII., Fig. 13. 
4 V. H. Blackman. “On the Cytological Features of Fertili¬ 
sation and Related Phenomena in Pinus silvestris ,L.” Phil. 
Trans. Roy. Soc. 190 B., 1898. 
3 A. A. Lawson. “The Gametophytes, Archegonia, Fertilisation, 
and Embryo of Sequoia sempervirens." Annals of Botany, 
Vol. XVIII., 1904, p. 1. 
* W. C. Coker. Loc. cit. 
