■2 14 
Agjies Robertson. 
The two sperm-nuclei are enclosed in a single cytoplasmic 
sheath. Only one is functional, but it is not distinguishable in size 
from the other. Fertilisation occurs early in September, that is 
between three and four months after pollination. The male cell 
contributes to the cytoplasmic sheath of the fusion nucleus. Wall 
formation is initiated when only four nuclei are present, and no 
trace was found of the extensive free cell-formation which has 
been described for Taxus and Cephalotaxus and is regarded as a 
primitive character. 
The number of chromosomes in the female gametophyte 
appears to be eight. 
X.—Conclusion. 
I began the study of the spore development and sexual organs 
of Torreya californica, not unprepared to find at any rate some 
Cycad-like traits, but this expectation has scarcely been realised. 
If I have counted the chromosomes correctly, the number agrees 
with Ceratozamia (and Taxus ) and differs from that usually found 
in Conifers ; but in no other point have I succeeded in recognising 
any additional evidence for the relationship of Torreya with the 
Cycads,—a relationship which is clearly suggested by the structure 
of the seed and seedling. 
EXPLANATION OF PLATES VII., VIII., and IX. 
Illustrating A. Robertson’s Paper on “The Sexual Organs and 
Fertilisation in TORREYA CALIFORNICA." 
nuc., nucellus ; i., integument; e., endosperm ; ep., “ epithelium ” of 
endosperm ; c., cuticle ; p.t., pollen-tube ; t.n., pollen-tube nucleus ; b.c., body¬ 
cell; s.c.n, stalk-cell nucleus; v.n., vegetative nucleus (either stalk or tube 
nucleus); J j functional male nucleus; <? 2 second male nucleus; j.c., 
jacket cell of archegonium; ar., central cell of archegonium ; ? egg- 
nucleus; m.c., neck cell of archegonium; pro., proembryo; r., rosette-cell; 
5 , suspensor ; t., tip cell. 
§ All the drawings are from material collected this year. 
[Where a figure is drawn from more than one microtome section 
the number of sections from which it is reconstructed is given 
just before the magnification]. 
Plate VI1. 
Fig. 1. Longitudinal section of a bi-nucleate embryo-sac. June 30th. Three 
sections ( x 400). 
Fig. 2. Radial longitudinal section of the base of a female prothallus shewing 
ordinary endosperm cells, poor in contents, and the “ epithelial ” layer at 
the base, followed by crushed nucellar tissue, g., a globule of unknown 
composition, turning yellow with Orange G. September 16th. (x 400). 
