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"The Power of Movement in Plants"


Apium graveolens.--The cotyledons at noon were horizontal, and at 10 P.M.
stood at an angle of 61o above the horizon.
Lactuca scariola (Compositae).--The cotyledons whilst young stood
sub-horizontally during the day, and at night rose so as to be almost
vertical, and some were quite vertical and closed; but this movement ceased
when they had grown old and large, after an interval of 11 days.
Helianthus annuus (Compositae).--This case is rather doubtful; the
cotyledons rise at night, and on one occasion they stood at 73o above the
horizon, so that they might then be said to have been asleep.
Ipomoea caerulea vel Pharbitis nil (Convolvulaceae).--The cotyledons behave
in nearly the same manner as those of the Anoda and Nankin cotton, and like
them grow to a large size. Whilst young and small, so that their blades
were from .5 to .6 of an inch in length, measured along the middle to the
base of the central notch, they remained horizontal both during the middle
of the day and at night. As they increased in size they began to sink more
and more in the evening and early night; and when they had grown to a
length (measured in the above manner) of from 1 to 1.


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