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14).--The movement of the stem of
a young plant, 4 inches in height, consisting of four internodes (the
hypocotyl included) besides a large bud
Fig. 70. Iberis umbellata: circumnutation of stem of young plant, traced
from 8.30 A.M. Sept. 13th to same hour on following morning. Distance of
summit of stem beneath the horizontal glass 7.6 inches. Diagram reduced to
half of original size. Movement as here shown magnified between 4 and 5
times.
on the summit, was traced, as here shown, during 24 h. (Fig. 70). As far as
we could judge the uppermost inch alone of the stem circumnutated, and this
in a simple manner. The movement was slow, and the rate very unequal at
different times. In part of its course an irregular ellipse, or rather
triangle, was completed in 6 h. 30 m.
(2.) Brassica oleracea (Cruciferae).--A very young plant, bearing three
leaves, of which the longest was only three-quarters of an inch in length,
was placed under a microscope, furnished with an eye-piece micrometer, and
the tip of the largest leaf was
[page 203]
found to be in constant movement.


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