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trivance or other to interfere with self-fertilisation and favour 
intercrossiog. The anthers are not always rotatory, but in such 
case their position and dehiscence are such as to render it im- 
possible for a bee to get at the nectary from the mouth of the 
tube without carrying off some of the pollen on its body, which 
it will convey to another flower ; while at the same time the 
position of the stigma, and its different periods of maturity, 
protect it from the pollen of its brother anthers. 
I would now illustrate the facts I have described by the phe- 
nomena presented in the fertilisation of some other plants. 
If a common mallow, or a hollyhock, be examined soon after 
it has expanded, the stamens will be seen rising up in the centre, 
and forming with their united filaments a tube, from the upper 
end of which the filaments again diverge, each to terminate in 
an anther cell, loaded with large grains of pollen. The ripe 
pollen drops in abundance from these anther cells, and may be 
seen lying at the bottom of the corolla. Here, at the points of 
junction of the separate petals, will be seen certain glandular 
bodies, one at each interval, which secrete a fluid which attracts 
bees and other insects. The fallen pollen will be seen adhering 
in quantities to this sticky secretion, so that an insect which 
comes to enjoy the nectar, can scarcely fail to carry off some 
grains attached to its head or body. At this time no stigma nor 
style is visible. This lies entirely out of sight in the tube of the 
filaments, and is, in fact, quite immature. It is only later on, 
when the pollen has been entirely, or almost* entirely, shed, that 
the stigmas make their appearance above the tube. When once 
they have emerged, their growth is rapid, and they soon assume, 
as they lengthen, such a position that an insect which visits the 
nectaries must in so doing impinge upon them, in which case it 
will leave upon them some of the pollen it has brought from a 
less mature flower. 
Intercrossing, then, in these plants is secured by the stamens 
and stigmas reaching their maturity at different periods. But 
it is to be noticed, that this is not the case with all the Malvaceae. 
There are some in which the stigmas are mature and protrude 
from the tube in the early period when the anthers are still 
charged with pollen, so that here self-fertilisation may occur 
with the greatest facility. Now, it is of great interest to note, 
• Ver}' frequently the stigmas make their appearance before all the pollen 
is shed ; and in such cases they may get some grains from their brother 
stamens. Ilut these will not be numerous ; probably seldom enough to pro- 
duce fecundation. For Giirtner has shown, that even thirty grains of mallow 
pollen are insufficient to fertilise a single seed ; but that when forty grains 
are applied to the stigma, a few seeds of small size may be formed. — 
Cf. Darwin, “ Animals and Plants,” ii. 3C4. 
