The movements of the cotyledons are interesting from their complexity and
rapidity, and in some other respects. The hypocotyl (2 inches high) of a
vigorous seedling was secured to a stick, and a filament with triangles of
paper was affixed to one of the cotyledons. The plant was kept all day in
the hot-house, and at 4.20 P.M. (June 20th) was placed under a skylight in
the house, and observed occasionally during the evening and night. It fell
in a slightly zigzag line to a moderate extent from 4.20 P.M. till 10.15
P.M. When looked at shortly after midnight (12.30 P.M.) it had risen a very
little, and considerably by
* 'Movements and Habits of Climbing Plants,' p. 33, 1875.
[page 48]
3.45 A.M. When again looked at, at 6.10 A.M. (21st), it had fallen largely.
A new tracing was now begun (see Fig. 35), and soon afterwards, at 6.42
A.M., the cotyledon had risen a little. During the forenoon it was observed
about every hour; but between 12.30 and 6 P.M. every half-hour. If the
observations had been made at these short intervals during the whole day,
the figure would have been too intricate to have been copied.
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