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
12 flowers fertilised by the mid-length stamens of the short-styled. These
stamens equal in length the pistil of the mid-styled.
Product of good seed in each capsule.
112 109
130 143
143 124
100 145
33 12
- 141
104
100 percent of these flowers yielded capsules. Each capsule contained, on an
average, 108.0 seeds; or, excluding capsules with less than 20 seeds, the
average is 116.7 seeds.
TABLE 4.24.3. Illegitimate union.
13 flowers fertilised by the shortest stamens of the long-styled.
83 12
0 19
0 85 seeds small and poor.
- 0
44 0
44 0
45 0
54 percent of these flowers yielded capsules. Each capsule contained, on an
average, 47.4 seeds; or, excluding capsules with less than 20 seeds, the average
is 60.2 seeds.
TABLE 4.24.4. Illegitimate union.
15 flowers fertilised by the longest stamens of the short-styled.
130 86
115 113
14 29
6 17
2 113
9 79
- 128
132 0
93 percent of these flowers yielded capsules. Each capsule contained, on an
average, 69.5 seeds; or, excluding capsules with less than 20 seeds, the average
is 102.8 seeds.
TABLE 4.24.5. Illegitimate union.
12 flowers fertilised by own-form longest stamens.
92 0
9 0
63 0
- 0
136?* 0
0 0
0
(4/6. * I have hardly a doubt that this result of 136 seeds in Table 4.24.5 was
due to a gross error. The flowers to be fertilised by their own longest stamens
were first marked by “white thread,” and those by the mid-length stamens of the
long-styled form by “white silk;” a flower fertilised in the later manner would
have yielded about 136 seeds, and it may be observed that one such pod is
missing, namely at the bottom of Table 4.24.1. Therefore I have hardly any doubt
that I fertilised a flower marked with “white thread” as if it had been marked
with “white silk.” With respect to the capsule which yielded 92 seeds, in the
same column with that which yielded 136, I do not know what to think. I
endeavoured to prevent pollen dropping from an upper to a lower flower, and I
tried to remember to wipe the pincers carefully after each fertilisation; but in
making eighteen different unions, sometimes on windy days, and pestered by bees
and flies buzzing about, some few errors could hardly be avoided. One day I had
to keep a third man by me all the time to prevent the bees visiting the
uncovered plants, for in a few seconds’ time they might have done irreparable
mischief. It was also extremely difficult to exclude minute Diptera from the
net. In 1862 I made the great mistake of placing a mid-styled and long-styled
under the same huge net: in 1863 I avoided this error.)
Excluding the capsule with 136 seeds, 25 percent of the flowers yielded
capsules, and each capsule contained, on an average, 54.6 seeds; or, excluding
capsules with less than 20 seeds, the average is 77.5.
TABLE 4.24.6. Illegitimate union.
12 flowers fertilised by own-form shortest stamens.
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