20 m., but the next day, being very cold, the time was 5 hrs. 10
m. A stick placed near a revolving stem was soon struck by the
petioles which stand out at right angles, and the revolving movement
was thus arrested. The petioles then began, being excited by the
contact, to slowly wind round the stick. When the stick was thin, a
petiole sometimes wound twice round it. The opposite leaf was in no
way affected. The attitude assumed by the stem after the petiole had
clasped the stick, was that of a man standing by a column, who throws
his arm horizontally round it. With respect to the stem's power of
twining, some remarks will be made under C. calycina.
Clematis Sieboldi.--A shoot made three revolutions against the sun at
an average rate of 3 hrs. 11 m. The power of twining is like that of
the last species. Its leaves are nearly similar in structure and in
function, excepting that the sub-petioles of the lateral and terminal
leaflets are sensitive. A loop of thread, weighing one-eighth of a
grain, acted on the main petiole, but not until two or three days had
elapsed. The leaves have the remarkable habit of spontaneously
revolving, generally in vertical ellipses, in the same manner, but in
a less degree, as will be described under C.
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