Male Gametes in Pines and Allied Conifers. 175 
cases were observed in which the pollen-tube, instead of growing 
straight through the nucellus to the archegonia, made its way along 
the side of the prothallus, and having gone some distance in this 
direction then turned in towards the prothallus. This is strikingly 
like the state of affairs which Lawson has described for Sequoia 
(12), and without intending to suggest that this points to any very 
close relationship between Sequoia and Pinus, I yet think that it 
strengthens the view that the ancestors of the Pines at one time 
possessed a wider distribution of archegonia than they do at 
present. It may be noticed that the division and subsequent 
developmental history of the products of the division of the 
central cell of the archegonium suggests a series parallel with that 
of the division and history of the products of the body cell of the 
pollen-grain. 
If the above theory of the cause of the inequalities and 
variations of the male apparatus of the conifers be accepted, it will 
be seen that these variations are connected with changes in the 
female apparatus. Goebel (9) has already suggested that the 
differences to be observed in the germination of Cycadean and Coni¬ 
ferous pollen-grains are connected with the structure of the ovule. 
It would therefore seem that the male gametophyte is comparatively 
plastic and liable to vary with changes in its environment, and a 
certain amount of caution is required in using data gained from it in 
discussing the phylogeny of any particular group. 
REFERENCES. 
1. Blackman, V. H. “ On the Cytological Features of Fertilization and 
related Phenomena in Pinus sylvcstris L.” Phil. 
Trans. Roy. Soc., 190. 1898. 
2. Chamberlain, C. J. “ Oogenesis in Pinus Laricio." Bot. Gaz. 27. 1899. 
3. Coker, W. C. “ Fertilization and Embryogeny in Ceplialotaxus For- 
tunei." Bot. Gaz. XLI1I. 1907. 
4. ,, ,, “The Gametophvtes and Embryo of Podocarpns." 
Bot. Gaz. XXXIII. 1902. 
5. Coulter, J. M. “Notes on the Fertilization and Embryogeny of 
Conifers.” Bot. Gaz. 23. 1897. 
6. Coulter, J. M. and Land, W. J. G. “ The Gametophytes and Embryo of 
Torreya taxifulia." Bot. Gaz. 39. 1905. 
7. Dixon, H. N. “ Fertilization of Pinus sylvcstris .” Ann. Bot. 1894. 
