T42 
Agnes Robertson. 
success of these two genera, whose structure is otherwise so diverse, 
to the winged pollen-grains, which would, in the matter of cross¬ 
fertilisation, give them a distinct advantage over their wingless 
competitors ? 
VI.— The Female “ Flowers.” 
The ovules of Torreya califomica occur on the shoots of the 
current year, especially near the base. In the axil of a foliage leaf 
an extremely short branch arises bearing two bracts, B and B', 
which stand to right and left. In the axil of each an ovule is 
produced with two pairs of bracts below it. The first pair, b x and 
b 2 , is placed at right angles to B and B', whilst the second pair, 
b 3 and b 4 , is parallel to B and B'. Between the ovules a 
rudimentary growing point occurs which, as an occasional abnor¬ 
mality terminates in a third ovule 1 , or produces an extra bract. 
Sections of a bud gathered on December 1st, disclosed young 
ovules already shewing the rudiment of nucellus and integument 
(Fig. 16). There is not much change during the winter, but in 
material collected on March 4th, the two bracts B and B' are 
discernible (Figs. 17a and b). Examination of ovules collected a 
fortnight later shews that by this date the bract of the lower pari 
remote from the axis has appeared, while its fellow has not yet 
developed (Fig. 18). Before the end of April the integument has 
over-topped the nucellus and the arillus has begun to appear (Fig. 
20b). Material collected on May 8th, and cut longitudinally shews 
the arrangement of the bracts and the different parts of the ovule 
very clearly (Figs. 21a, b, c). The little swelling between the 
ovules which represents the growing point of the dwarf shoot does 
not occur exactly in the median plane of the ovules, and so is not 
visible in the section drawn, but its position as seen a few sections 
further on is indicated by a dotted line. The embryo-sac mother¬ 
cell has not yet become distinguishable from its neighbours. 
At the time of pollination, three or four weeks later, a drop of 
liquid exudes from the micropyle, and in this the pollen grains are 
caught. 
VII.— Development of the Megaspore. 
In material collected on May 21st, the embryo-sac mother-cell 
is visible for the first time (Figs 22a, b, c). The nucleus is large 
and resting, and the protoplasm packed with starch, while the 
1 A third ovule in this position is recorded as an abnormality 
in the related Torreya nucijera by Strasburger (Angiospermen 
und Gymnospcrmen, 1879). 
