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In the greenhouse the cotyledons of numerous quite young seedlings were open in the middle of the day (Feb. 9th) & formed together an angle, estimated at 30°—. At 6° P.m, when it was almost dark, they were nearly closed

Perhaps introduce under Heliotrop— & say here movement cd not be observed

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Ch I) Lychnis Githago segetum Sleep of Cotyledon & Light?

& next morning (Feb. 10th at 8° a.m. they were still completely closed or asleep. The seedlings were then placed in a box with a glass cover in a north N.E room, so as to be feebly illuminated from above whilst the circumnutation of the hypocotyl was being observed.

The Cotyledons did not open in the least all day, nor on the following morning (Feb 11th) as long as they were dimly illuminated. At 12° 30' they were carried back to the greenhouse, & in 2 1/2 hours, though the day was very dull & misty, the cotyledons of some few of the plants began to open, & after an additional 1 1/2 hours they formed together were open to the extent of between 20° & 30°.

By this time the hypocotyls The stems of all the plants had become greatly bowed to the chief source of light: At 7° 30' P.m all the cotyledons were completely closed. On the following morning (Feb 12th) at 7° 30' a.m they were still closed, but at 9° partially open, by which time the sun was shining; at 12° 30' they were open to the extent of 38° & at 4° 30' to 62°; at 7° 30' P.m they were almost &. at 10° 30' completely

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Ch I) Lychnis Githago segetum

(shut. On the following morning (Feb. 13th) they behaved like most sleeping plants, for they awakened early & the cotyledons were separate at 7° a.m. On this same day the plants were placed at 1° P.m in a dark cup-board, but they did not begin to close till late in the evening, & they never again either on this night or the following ones became completely closed. We have not met with hardly any other instance in which the movements of the cotyledons are so directly governed by the light, for they remained quite shut during a whole day & on the following morning, when only illuminated only feebly from above,— that is during 40° including two nights.