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Darwin, Charles, 1809-1882

"The Movements and Habits of Climbing Plants"

42 m. { 1 hr. 14 m., to the light
{ 1 hr. 28 m.: difference 14 m.
{Semicircle, from the light in
2nd circle was made in 2 hrs. 47 m. { 1 hr. 17 m., to the light 1 hr.
{ 30 m.: difference 13 m.
Ipomaea jucunda (Convolvulaceae) moves against the sun, placed in my
study, with windows facing the north-east. Weather hot.
{Semicircle, from the light in
1st circle was made in 5 hrs. 30 m. { 4 hrs. 30 m., to the light 1
hr.
{ 0 m.: difference 3 hrs. 30 m.
2nd circle was made in 5 hrs. {Semicircle, from the light in
20 m. (Late in afternoon: { 3 hrs. 50 m., to the light 1
hr.
circle completed at 6 hrs. 40 m. { 30 m.: difference 2 hrs. 20 m.
P.M.)
We have here a remarkable instance of the power of light in retarding
and hastening the revolving movement. (See ERRATA.)
Convolvulus sepium (large-flowered cultivated var.) moves against the
sun. Two circles, were made each in 1 hr. 42 m.: difference in
semicircle from and to the light 14 m.
Rivea tiliaefolia (Convolvulaceae) moves against the sun, made four
revolutions in 9 hrs.


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