40 P.M. in a slightly
zigzag course, the actual distance travelled by the apex being .67 of an
inch. During the night the leaf fell, whereas it ought to have risen; and
by 7 A.M. on the following morning it had fallen .23 of an inch, and it
continued falling until 9.40 A.M. It then rose until 10.50 P.M., but the
rise was interrupted by one considerable oscillation, that is, by a fall
and re-ascent. During the second night it again fell, but only to a very
short distance, and on the following morning re-ascended to a very short
distance. Thus the normal course of the leaf was greatly disturbed, or
rather completely inverted, by the absence of light; and the movements were
likewise greatly diminished in amplitude.
We may add that, according to Mr. A. Stephen Wilson,* the young leaves of
the Swedish turnip, which is a hybrid between B. oleracea and rapa, draw
together in the evening so much "that the horizontal breadth diminishes
about 30 per cent. of the daylight breadth." Therefore the leaves must rise
considerably at night.
(5.) Dianthus caryophyllus (Caryophylleae, Fam.
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