As the filaments were fixed in the three last cases to one of the
cotyledons, and as the hypocotyl was left free, the tracings show the
movement of both organs conjoined; and we now wished to ascertain whether
both circumnutated. Filaments were therefore fixed horizontally to two
hypocotyls close beneath the petioles of their cotyledons. These seedlings
had stood for two days in the same position before a north-east window. In
the morning, up to about 11 A.M., they moved in zigzag lines towards the
light; and at night they again became almost upright through apogeotropism.
After about 11 A.M. they moved a little back from the light, often crossing
and recrossing their former path in zigzag lines. the sky on this day
varied much in brightness, and these observations merely proved that the
hypocotyls were continually moving in a manner resembling circumnutation.
On a previous day which was uniformly cloudy, a hypocotyl was firmly
secured to a little stick, and a filament was fixed to the larger of the
two cotyledons, and its movement was traced on a vertical glass. It fell
greatly from 8.52 A.M., when the first dot was made, till 10.55 A.M.; it
then rose greatly until 12.17 P.M. Afterwards it fell a little and made a
loop, but by 2.22 P.M. it had risen a little and continued rising till 9.23
P.M., when it made another loop, and at 10.30 P.M. was again rising. These
observations show that the cotyledons move
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vertically up and down all day long, and as there was some slight lateral
movement, they circumnutated.

Fig. 9. Brassica oleracea: circumnutation of hypocotyl, in darkness, traced
on a horizontal glass, by means of a filament with a bead fixed across its
summit, between 9.15 A.M. and 8.30 A.M. on the following morning. Figure
here reduced to one-half of original scale.

The cabbage was one of the first plants, the seedlings of which were