30 P.M. on the
8th, the stem moved a considerable distance in a zigzag line in the same
general direction. During the night of the 8th it moved to some distance at
right angles to its former course, and next morning (9th) stood for a time
almost still. At noon on the 9th a new tracing was begun (see Fig. 71),
which was continued till 8 A.M. on the 11th. Between noon on the 9th and 5
P.M. on the 10th (i.e. in the course of 29 h.), the stem described a
circle. This plant therefore circumnutates, but at a very slow rate, and to
a small extent.
(5.) Tropaeolum majus (?) (dwarfed var. called Tom Thumb); (Geraniaceae,
Fam. 47).--The species of this genus climb by the
[page 204]
aid of their sensitive petioles, but some of them also twine round
supports; but even these latter species do not begin to circumnutate in a
conspicuous manner whilst young. The
Fig. 72. Tropaeolum majus (?): circumnutation of stem of young plant,
traced on a horizontal glass from 9 A.M. Dec. 26th to 10 A.M. on 27th.
Movement of bead magnified about 5 times, and here reduced to half of
original scale.
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