8 
NATURE NOTES. 
fertilised in any other way, the anthers being placed in direct 
contact with the stigmas in one and the same flower. Indeed 
in man)' such cases the flowers scarcely or at all open, there 
being no necessity for doing so. It is worth while remarking 
that regularly self-fertilising as well as wind-fertilised flowers 
are the most abundant and the most widely dispersed of all 
flowering plants over the world.* 
When we examine flowers which are specially adapted to 
the visits of insects, what strikes one is the extraordinary 
amount of minute details in every part of the flower, which all 
conspire to enable the insect to extract honey or pollen for food, 
and at the same time insure that it shall be dusted in such a 
way as to compel it to carry the pollen direct to the stigma of 
another flower when it visits it. The pistil is always so 
situated as to receive the pollen on the stigma. Thus in all 
flowers growing close to the stem, as the Dead Nettle, Gladiolus, 
and Snapdragon, the flower is “ irregular,” that is, the parts are 
of different shapes. The flower can only be visited in one way, 
or from the front. Hence there is a large petal or “lip ” acting 
as a landing place, or, if no petal be there, the stamens are bent 
downwards, and then turn up to support the weight of the in- 
sect, as in the Horse-chestnut and Rhododendron. The honey 
gland is always so placed that the insect can reach it most 
easily. It is, moreover, perfectly correlated to the position 
of the anthers and stigmas. Thus, if the Gladiolus be examined, 
the three anthers will be seen to be arched over the front petals, 
and strike a bee on the back or thorax, the three-forked stigma 
overhangs them and readily hits the same place on the insect. 
In the Crocus, however, which belongs to the same family as the 
Gladiolus, the three stamens are erect around the style, which 
terminates in a brush-like stigma. The tube of the flower is so 
contracted that the bee cannot walk down it, but alighting on 
the stigma crawls head downwards, grasping the stamens with 
its legs. The anthers conveniently burst outwards, and so dust 
the insect in this case on the underside. On flying off to another 
flower it settles on the brush, and the pollen is then removed by 
it from the bee and fertilises the flower. 
The question arises, How have these innumerable differ- 
ences in floral structure come into existence ? How have all 
the myriads of forms of flowers been made ? The reply seems 
to be that they have grown in response to the irritations set up 
by insects, similarly as the leaves of water plants have grown in 
form and anatomical structure under the action of their environ- 
ment. 
What we know about the properties of the living substance 
* It was formerly thought by Mr. Darwin that self-fertilisation was in some 
way injurious to plants, and that, if persisted in, they would gradually die out. It 
is now known that this idea was based on an entirely erroneous supposition, and 
was not deduced from actual observations of living plants. Mr. Darwin himself 
latterly conceded the importance and recognized the frequency of the process. 
