THE SELF-FERTILIZATION OF PLANTS. 
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Fig. 12 
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, Viola tricolor. The corolla has withered, so that the spurred petal 
has pressed the pollen into the orifice, and has remained clinging 
to it. Both the petal and stamens have become elevated by the 
growth of the ovary. 
This represents the style and globular stigmatic “head” of a self- 
fertilising form of V. tricolor var. arvensis, in which the pla- 
centiferous tissue had grown up like a pillar and protruded from 
the orifice in the form of a knob. Pollen tubes were penetrating 
the centre of the pillar in abundance. 
Vertical section of the preceding. 
Another self-fertilising adaptation, in which the placenta had grown 
over the “ lip,” and was prolonged into a kind of tongue which 
thus “ licked ” up the pollen from the spurred petal. 
Apex of pistil and stamens of Polygala vulgaris. The anthers are 
emptying themselves of pollen into the spoon-shaped extremity 
of the style. 
(after Hildebrand). The stigma is seen to become pollinated by 
bending back into the pollen. 
A form in which the anthers are on a level with the stigma, into 
which abundance of pollen-tubes had penetrated. 
A self-fertilising bud of Spergula arvensis (Jan. 1874). 
Same with calyx and corolla removed. 
A flower of Ohickweed. This, as also the Spergula, has the number 
of stamens reduced to three. 
The stigmas of Malva rotundifolia represented as recurved amongst 
the anthers, and becoming self-fertilised. 
Stamens and pistil of Linurn catharticum. 
Stamens and stigmas of Pelargonium zonale. The stigmas are 
recurved amongst the anthers and becoming pollinated by them. 
Cleistogamous flower-bud of Oxalis Acetosella. 
Calyptriform corolla of the same. 
Anthers of same united together by filamentous processes. (It is 
not quite clear what these are, but probably not pollen-tubes.) 
Pistil of same, with anthers of two of the latter stamens in contact 
with the short stigmas. The lower anthers are partly aborted, 
two filaments only represented. 
Cleistogamous flower-bud of Impatiens fulva. 
Same with calyx and corolla partly detached from the pistil (after 
Bennett). 
Stamens of same. 
Stamens and pistil of small-flowered leguminous plant, such as 
Medicago denticulata, the ten anthers being clustered round 
the stigma, both maturing together. 
A stamen and a flower of Agrimonia, the corolla removed, with 
stamens incurved, some time after expansion. 
First stage of Circcea lutetiana on expansion. The anthers are close 
to the stigma. 
The second stage of the same, the anthers now spread away. The 
stigma having been pollinated, is drawn to one side by mechanical 
adhesion to the anther. 
