RECORD: Darwin, C. R. 1879.06.17. Ipomœa nil / Proof sheet of Forms of flowers. CUL-DAR209.7.59-62. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)
REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 8.2022. 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 volumes CUL-DAR209.7-8 contain notes on heliotropism (phototropism) for Darwin's book Movement in plants (1880).
[59]
June 17. 1879 Ipomœa (Pharbitis) cærulea & purpurea exposed to N.E Window on day rather bright, but sometimes cloudy — rest of room dark darkened— muslin blind up— Light acted strongly on Hypocotyl of some young seedlings.— Did not draw the stems to light — Plants about a foot in height; some rather taller & some shorter
name & Pot
Pot I I. cærulea
Pot II
Pot III do young Plant This started late in day I. purpurea IV
V
VI
VII
12) |
Semicircle moving from light
minutes 70 84 68 72 78 76 82 72 49 78 10)729 81 87 72 75 58 62 85 85 69 73 66 76 12) 889 average 74.1 5 729 [+] 889 [=] 1618 [÷] 22 aver 73.5 minutes |
Semicircle moving To light
52 75 95 66 77 74 62 104 81 85 771 52 70 66 79 78 81 68 76 84 63 72 67 12) 856 71.7 5 771 [+] 856 [=] 1627 [÷] 22) 73.95 |
Observations begun at 6° 45' am & finished at about 2° P.m.
Probable error hardly as much as 5m. (Although the stems are thus not in the least Heliotropic— the Hypocotyls of young seedlings of Ipomoea cærulea are very strongly Heliotropic, bending in few hours at right angles towards light— good case gradation towards Ivy.)
average 72.9 — 77.1
Extreme fluctuations in rate in same plant & different plants— In moving from light varied between 87m — in moving to light varied from 104 to 52 m.m.— The first semicircle was quicker to light than from it in 6 out of 7 cases |
It is evident travel at same average rate 2 & from light.
[60]
June 17th 1879 Ipomœa cærulea — N.E— window
Moderately bright day High-Cloud— Changeable Room darkened, except 1 window
[sketch] Hypocotyls strong Heliotropic
(1) 6° 45 facing to light — (Young Plant)
[data not transcribed]
[60]
[Proof sheet of Forms of flowers, published pp. 88-9.]
[61]
June 17th 1879 Ipomoea purpurea N.E. window
[data not transcribed]
[61v]
[Proof sheet of Forms of flowers, published pp. 87-8.]
[62]
First in moving
Moving from light
Moving to light
[calculations]
Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)
File last updated 25 September, 2022