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
If we compare the weight from an equal number of plants, and from an equal
number of umbels, and from an equal number of capsules of the two forms, we get
the following results:--
TABLE 1.2.
Column 1: Plant.
Column 2: Number of Plants.
Column 3: Weight of Seed in grains.
...
Column 4: Number of Umbels.
Column 5: Weight of Seed.
...
Column 6: Number of Capsules.
Column 7: Weight of Seed in grains.
Short-styled cowslips : 10 : 92 :: 100 : 251 :: 100 : 41.
Long-styled cowslips : 10 : 70 :: 100 : 178 :: 100 : 34.
So that, by all these standards of comparison, the short-styled form is the more
fertile; if we take the number of umbels (which is the fairest standard, for
large and small plants are thus equalised), the short-styled plants produce more
seed than the long-styled, in the proportion of nearly four to three.
In 1861 the trial was made in a fuller and fairer manner. A number of wild
plants had been transplanted during the previous autumn into a large bed in my
garden, and all were treated alike; the result was:--
TABLE 1.3.
Column 1: Plant.
Column 2: Number of Plants.
Column 3: Number of Umbels.
Column 4: Weight of Seed in grains.
Short-styled cowslips : 47 : 173 : 745.
Long-styled cowslips : 58 : 208 : 692.
These figures give us the following proportions:--
TABLE 1.4.
Column 1: Plant.
Column 2: Number of Plants.
Column 3: Weight of Seed in grains.
...
Column 4: Number of Umbels.
Column 5: Weight of Seed in grains.
Short-styled cowslips : 100 : 1585 :: 100 : 430.
Long-styled cowslips : 100 : 1093 :: 100 : 332.
The season was much more favourable this year than the last; the plants also now
grew in good soil, instead of in a shady wood or struggling with other plants in
the open field; consequently the actual produce of seed was considerably larger.
Nevertheless we have the same relative result; for the short-styled plants
produced more seed than the long-styled in nearly the proportion of three to
two; but if we take the fairest standard of comparison, namely, the product of
seeds from an equal number of umbels, the excess is, as in the former case,
nearly as four to three.
Looking to these trials made during two successive years on a large number of
plants, we may safely conclude that the short-styled form is more productive
than the long-styled form, and the same result holds good with some other
species of Primula. Consequently my anticipation that the plants with longer
pistils, rougher stigmas, shorter stamens and smaller pollen-grains, would prove
to be more feminine in nature, is exactly the reverse of the truth.
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.
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account