The Different Forms of Flowers on Plants of the Same SpeciesDarwin, Charles
Science
The Different Forms of Flowers on Plants of the Same Species
Darwin, Charles
Fertilization of plants; Heterostylism; Plant physiology; Plants -- Variation; Pollination
This short-styled plant produced perfectly sound pollen, as viewed under the
microscope. During 1866 it was freely and legitimately fertilised by other
illegitimate plants belonging to the present and the following class, both of
which include many highly fertile plants. Under these circumstances it yielded
from eight capsules an average of 100.5 seeds, with a maximum of 123 and a
minimum of 86; so that it produced 121 per cent of seeds in comparison with the
normal standard. During 1864 it was allowed to be freely and legitimately
fertilised by legitimate and illegitimate plants, and yielded an average, from
eight capsules, of 104.2 seeds, with a maximum of 125 and a minimum of 90;
consequently it exceeded the normal standard, producing 125 per cent of seeds.
In this case, as in some previous cases, pollen from legitimate plants added in
a small degree to the fertility of the plant; and the fertility would, perhaps,
have been still greater had not the summer of 1864 been very hot and certainly
unfavourable to some of the plants of Lythrum.
PLANT 23.
This short-styled plant produced perfectly sound pollen. During 1866 it was
freely and legitimately fertilised by the other illegitimate plants specified
under the last experiment, and eight capsules yielded an average of 113.5 seeds,
with a maximum of 123 and a minimum of 93. Hence this plant exceeded the normal
standard, producing no less than 136 per cent of seeds.
PLANT 24.
This long-styled plant produced pollen which seemed under the microscope sound;
but some of the grains did not swell when placed in water. During 1864 it was
legitimately fertilised by legitimate and illegitimate plants in the same manner
as Plant 22, but yielded an average, from ten capsules, of only 55 seeds, with a
maximum of 88 and a minimum of 24, thus attaining 59 per cent of the normal
fertility. This low degree of fertility, I presume, was owing to the
unfavourable season; for during 1866, when legitimately fertilised by
illegitimate plants in the manner described under Number 22, it yielded an
average, from eight capsules, of 82 seeds, with a maximum of 120 and a minimum
of 67, thus producing 88 per cent of the normal number of seeds.
PLANT 25.
The pollen of this long-styled plant contained a moderate number of poor and
shrivelled grains; and this is a surprising circumstance, as it yielded an
extraordinary number of seeds. During 1866 it was freely and legitimately
fertilised by illegitimate plants, as described under Number 22, and yielded an
average, from eight capsules, of 122.5 seeds, with a maximum of 149 and a
minimum of 84. Hence this plant exceeded the normal standard, producing no less
than 131 per cent of seeds.]
CLASS 6. ILLEGITIMATE PLANTS RAISED FROM MID-STYLED PARENTS FERTILISED WITH
POLLEN FROM THE SHORTEST STAMENS OF THE LONG-STYLED FORM.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account