FERTILIZATION OF CATTLEYA LABIATA. 401 
had reached the apex of the placenta. The flowers in the three 
sets were now equally advanced; and from this time up to 
the conclusion of the observations scarcely any perceptible dif- 
ference in condition was noticeable between them. From these 
and the previous observations, it now became very evident that 
the time which must elapse between the pollination of the flower 
and the impregnation of the ovules would be considerably longer 
than we anticipated. l 
It is now time to turn to the ovary itself, and to take note of 
the changes that took place there from the time of pollination 
till the impregnation of the ovules. The very ru- Fig. 7. 
dimentary state of these at the epoch of the ex- e 
pansion of the flowers has been already mentioned. 
Fig. 7 shows transverse sections, natural size, in 
three different and successive stages of develop- 
ment—(A) shortly after the expansion of the flower 
and before pollination : (B)a fortnight after polli- 
nation ; the change of form that had taken place 
in this short interval is very striking ; the outline 
had chan ged from circular to triangular ; the simple 
sunk lines of the earlier stage had widened into ee 
wedge-shaped clefts, dividing the whole into three =~ 5 
well-marked carpellary lobes; each lobe has attained 
an almost triangular form by the enlargement of the placenta, 
and by the thickening of the walls of the ovary itself: (C) shows 
the further development about a Fig. 8. 
month after pollination ; the 
placenta and rudimentary ovules 
had then began to assume a more 
definite form, although no signs 
of impregnation of the latter 
could be detected. On the day 
the last-mentioned section was 
made the  pollen-tubes were 
found to have entered the ovary, 
and were pushing downwards 
along the sides of the placentas 
among the ovules. The condi- 
tion of the ovules themselves 
at the same date is represented in fig. 8, where an enlarged 
View of a minute section is given; it is there shown that they 
