Darwinism stated by Darwin himself · Charles Darwin
THE SLEEP OF THE PLANTS.
Considering that leaves in assuming their nyctitropic positions often move through an angle of 90°; that the movement is rapid in the evening; that in some cases it is extraordinarily complicated; that with certain seedlings, old enough to bear true leaves, the cotyledons move vertically upward at night, while at the same time the leaflets move vertically downward; and that in the same genus the leaves or cotyledons of some species move upward, while those of other species move downward--from these and other such facts, it is hardly possible to doubt that plants must derive some great advantage from such remarkable powers of movement.
Text from Project Gutenberg, public domain in the United States.