3 1 8 Oliver . — On Save odes sanguined . Torr. 
14). At an earlier stage, at the time when the tapetal layer 
is breaking down, and immediately after the division of the 
pollen-mother-cells, the division into two cells in each pollen- 
grain is very clearly shown (Figs. 10, 11, and 12). These cells 
are unequal ; the larger one contains a larger nucleus, often 
with two nucleoli at this time ; the other, small and bi-convex, 
a much smaller nucleus. It is the larger nucleus that is after- 
wards spindle-shaped and constitutes the generative nucleus 
of the pollen-grain. There is an absolute separation of the 
protoplasmic bodies of the two cells within the pollen-grain ; 
later however they fuse. Occasionally the division is found to 
be into equal parts (Fig. 15). The division of the mother-cells 
into pollen-grains takes place in the ordinary, dicotyledonous 
manner, the pollen-grains lying, as tetrads, in the mother-cells 
(Fig- 9)- 
A great number of pollen-grains is present on mature 
stigmas, and the pollen-tubes may be very readily dissected 
out from the style and ovary. In these tubes very large 
plugs are developed cutting off the lumen of the younger 
portion from the lumen of the older. These plugs arise first as 
annular cushions on the inside of the wall whereby the lumen 
is constricted. This goes on until the cavity at that point is 
obliterated (Fig. 16, a and b). Deposition of substance often 
continues till the pollen-tube is plugged for a length of *25 mm. 
Often the thickening is very irregular and recalls the callus- 
depositions in the trumpet -hyphae of certain Laminarieae (cf. 
Fig. 16, c, d , and e). No layers of stratification are demon- 
strable even with the highest powers of the microscope, nor 
after using re-agents. 
The Ovary has a very broad attachment to the receptacle. 
Its horizontal diameter exceeds by more than one-third its 
vertical. It is produced upwards into an erect style, bearing 
a 5-lobed stigma. The whole height of the gynaeceum is 
about two-thirds that of the corolla. Externally the ovary 
is prominently 10-lobed, each lobe projecting between two 
stamens (Fig. 3). Each lobe is continued down into a nectar- 
secreting region (u, Figs. 3 and 17), and in longitudinal section 
