[40]

506

(Erythrina sleep)

[in another hand:] ? climbing plants

greater degree, describing four irregular ellipses; & by 3 P.m it had risen into a horizontal position. By 7.15 Pm. it was vertically dependent & asleep, but continued to circumnutate as long as observed until 11° P.m.)

Erythrina corallodendron: The movement only of the terminal leaflet were traced: during the second day it oscillated four times up & down between 8 a.m & 4 P.m, after which hour the great nocturnal fall commenced. On the third day, the movement was equally great in amplitude, but was remarkably simple, for the leaflet rose in an almost perfectly straight line from 6 50 am to 3 P.m, & then sank down, in a straight line until vertically dependent & asleep.

Apios tuberosa & Phaseolus vulgaris: the leaflets of both these plants sink vertically down at night. The petiole of the a young leaf of the latter plant, cultivated in a pot in the greenhouse rose 16°, & of an older leaf 10° at night the same time night. With plants of the Phaseolus growing out of doors, the leaflets apparently do not sleep until somewhat late in the season; for on the night of July 11th & 12th

[40v]

[calculations not transcribed]

My Father's manuscript

Horace Darwin

Jan 24. 1897