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Darwin, Charles, 1809-1882

"The Different Forms of Flowers on Plants of the Same Species"


Echium vulgare (BORAGINEAE).
The ordinary hermaphrodite form appears to be proterandrous, and nothing more
need be said about it. The female differs in having a much smaller corolla and
shorter pistil, but a well-developed stigma. The stamens are short; the anthers
do not contain any sound pollen-grains, but in their place yellow incoherent
cells which do not swell in water. Some plants were in an intermediate
condition; that is, had one or two or three stamens of proper length with
perfect anthers, the other stamens being rudimentary. In one such plant half of
one anther contained green perfect pollen-grains, and the other half yellowish-
green imperfect grains. Both forms produced seed, but I neglected to observe
whether in equal numbers. As I thought that the state of the anthers might be
due to some fungoid growth, I examined them both in the bud and mature state,
but could find no trace of mycelium. In 1862 many female plants were found; and
in 1864, 32 plants were collected in two localities, exactly half of which were
hermaphrodites, fourteen were females, and two in an intermediate condition. In
1866, 15 plants were collected in another locality, and these consisted of four
hermaphrodites and eleven females. I may add that this season was a wet one,
which shows that the abortion of the stamens can hardly be due to the dryness of
the sites where the plants grew, as I at one time thought probable.


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