From R. I. Lynch   [28 August 1877]

Erythrina Crista-galli1

Large plant in greenhouse

—First observed at 9.30 p.m. when the leaflets were slightly depressed but scarcely so much as to suggest the condition of sleep. Taking a single leaf, the distances of the tips of the leaflets from the floor were measured, and also their distances from insertion of petiole. At 9.30 a.m. this morning the leaflet-tips were each about an inch and a half higher above floor level, partly by rising of petiole. Besides being elevated by movement of petiole were also moved away from point of insertion by the rising of petioles—the apex of terminal leaflet in a distance of 214 inches and the apices of the other two in a distance of 12 inch and 1 inch respectively

Large specimen out of doors.

—This tree was observed at 7 p.m., 9 p.m., and 9 a.m. No difference in the general appearance of the foliage could be detected. The leaflet-tips (some turned upwards) of three leaves were measured from insertion of petiole at 9 p.m.

At 9 a.m. this morning the leaflets of two leaves could not be said to have changed position. The other—a younger leaf—however, had decidedly altered the position of its leaflets, the terminal one being slightly raised and the others with their apices more towards the insertion of petiole.

The leaflets of the specimen indoors are all in similar corresponding position, while those of the last mentioned tree point in various directions, the terminal leaflets in particular have a tendency to turn upwards

Erythrina crista-galli is the cockspur coral tree. CD had asked Lynch to observe plants of this species to see whether they slept (see letter to R. I. Lynch, 23 August [1877] and n. 4).

Please cite as “DCP-LETT-11116,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-11116