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"The Power of Movement in Plants"

--The cotyledons of some seedlings having well-developed
leaves rose to an angle of about 45o at night; and even after 3 or 4 whorls
of leaves had been formed, the cotyledons rose at night considerably above
their diurnal horizontal position.
Cassia mimosoides.--The cotyledons of this Indian species, 14 days after
their first expansion, and when a leaf had been formed, stood during the
day horizontal, and at night vertical.
Cassia sp? (a large S. Brazilian tree raised from seeds sent us
[page 117]
by F. M?ller).--The cotyledons, after 16 days from their first expansion,
had increased greatly in size with two leaves just formed. They stood
horizontally during the day and vertically at night, but were not
afterwards observed.
Cassia neglecta (likewise a S. Brazilian species).--A seedling, 34 days
after the first expansion of its cotyledons, was between 3 and 4 inches in
height, with 3 well-developed leaves; and the cotyledons, which during the
day were nearly horizontal, at night stood vertical, closely embracing the
young stem. The cotyledons of another seedling of the same age, 5 inches in
height, with 4 well-developed leaves, behaved at night in exactly the same
manner.


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