After three-quarters of an hour the stem began to curve upwards,
quickly during the first two hours, but much more slowly during the
afternoon and night,
[page 495]
and on the following day. During the second night it fell a little, and
circumnutated during the following day; but it also moved a short distance
to the right, which was caused by a little light having been accidentally
admitted on this side. The stem was now inclined 60o above the horizon, and
had therefore risen 70o. With time allowed it would probably have become
upright, and no doubt would have continued circumnutating. The sole
remarkable feature in the figure here given is the straightness of the
course pursued. The stem, however, did not move upwards at an equable rate,
and it sometimes stood almost or quite still. Such periods probably
represent attempts to circumnutate in a direction opposite to
apogeotropism.
Fig. 182. Cytisus fragrans: apogeotropic movement of stem from 10o beneath
to 60o above horizon, traced on vertical glass, from 8.30 A.M. March 12th
to 10.30 P.M. 13th.
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