RECORD: Darwin, C. R. & Francis Darwin. [ny].09.19-20. Pistia stratiotes. CUL-DAR209.3.280. (John van Wyhe ed., 2002-. The Complete Work of Charles Darwin Online, http://darwin-online.org.uk/)
REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 12.2022. RN1
NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced with permission of the Syndics of Cambridge University Library and William Huxley Darwin. The volume CUL-DAR209.3 contains materials for Darwin's book Movement in plants (1880).
[280]
35 Pistia stratiotes— Sep 19 (Temperature varies between 18 1/2 & 23 1/2 C
Glass filament gummed to one leaf– & the angle made by the filament read 14 times between 9 am & 11·50 pm.
Sep 19– 9 am /— 32º above horizon
3.34 pm / 10º above horizon
11.50 pm / 55º above horizon
The angles at 3.34 pm & 11.50 pm were the lowest & highest observed; therefore the leave rises through 45º
On Sep 20th the leaf was 10º above Horizon at 8.25am & remained at about 15º above horizon, till sometime after 3.16 pm; at 5.40 pm when it was next looked at it was 23º above; & at 9.30pm it was 58º above In this case so that the the total rise was on the day 48º from 10º above at 8h 25m am to 58º above at 9.30 pm
On Sep 19th it only rose it did not rise from its lowest point ie 1 10º above hor at all till 4.29 pm & by 4.53 it was only 13º above; when next examined at 5.48 it was 22º above, & at 6.40 33º above, so one may say it began to rise between 5 & 6 I think
Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)
File last updated 24 January, 2023