RECORD: Darwin, C. R. 1879.06.21-07.04. Cucurbita ovifera. CUL-DAR209.11.121-124. (John van Wyhe ed., 2002-. The Complete Work of Charles Darwin Online, http://darwin-online.org.uk/)
REVISION HISTORY: Transcribed by Christine Chua and John van Wyhe, edited by John van Wyhe 7.2023. RN2
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-DAR209.11 contains material for Darwin's book Movement in plants (1880).
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June 21' 1879. 9º 10' a.m. Cucurbita ovifera— — Radicles long one extended horizontally over water.— dots 9 mm from apex. — tips of 5 well cauterised to see whether Geotropism destroyed
(1) caustic 4º 50 7º 40' 12 1/2 mm quite horizontal (22d 8º a m — still horizontal 24 mm!)
(2) caustic 4º 50' 12 1/2 mm quite horizontal inclined upwards but straight— owing to bending of Hypocotyl 22' 8º a.m. These 3 in same state as yesterday & like those without caustic}
(3) caustic 4º 50 as much geotropic as any are below. ie inclined, but straight do
(4) caustic 4º 50' like (3) do.—
This page of no use Radicles too long & old
(5) caustic 4º 50' quite horizontal 11 mm (22d 8º. a.m. still quite horizontal 16 mm)
(6) 0) 4º 50 slightly inclined downward owing to moving of Hypocotyl — This seedling with long radicles very little geotropic
(7) 0 4º 50 straight & only all inclined — owing to movement of Hypocotyl
(21st 4º 50 P.m It is no use tracing with very long radicles, as the apices are very little geotropic, whilst the hypocotyl just emerging from seed is & turn downwards to cause doubling of Hypocotyl.— The cotyledon being fixed the whole radicle is curved downwards — This important for I have not detected this before—In this case viz (1) & (5) radicle had remained horizontal & yet had gone considerably towards apex — This offers a shade of very important evidence
(8) 0 like (7)
(9) (0) like (7)
(10) (0) like (7) (22d 8am The 5 without caustic are now all geotropic. but this is owing to bending of hypocotyl.
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June 24th 4º 50 P.m. 1879 Jar D Cucurbita ovifera— Radicles only .2 to .3 of inch in length quite straight (seeds germinated on end in Peat) extended horizontally over water— Tips rubbed with caustic of half specimens
For Geotropism
(1) caustic 10º 5 P.m aft 5º. 15' Hardly geotropic, but turned rather laterally .38 long:
(2) caustic 10. 5' P.m —strong geotropic: oddly black tip in this & (3) larger than in others!!
(3) caustic 10. 5' P.m strongly geotropic
(4) caustic 10. 5' P.m quite Horizontal .31 long
(5) caustic 10 5 P.m quite Horizontal .44 long
(6) Control 10º 5' almost Horizontal .35 long
(7) (1) 10º 5. P.m.— all following 6 radicles rectangularly geotropic.
(8) (1)
(9) (0) 7 Controls
10 (0)
(11) (0)
12 (0)
June 25th 7º 45' a.m. All 6 with caustic are now geotropic, but none vertically so— movements from 25º to 35º from the vertical & 2 still move from vertical even 50º— Whereas the 6 Controls are mostly vertical & present a strong contrast with other six
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⨀ ⨀ ⨀ ⨀ ⨀ ⨀ ⨀
5. 5 [+] 5. 5 [=] 11. 0 .85 [=] 10. .9.5
10. 9.5 [÷] 5 [=] 2.19.
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Jun 25th 1879 8º 25' a.m Cucurbita extended horizontally over water with tips caustic for Geotropism— radicles from 3 or .4 in length to 1/4 of inch & a few even infer, not measured. —
(1) caustic
(2) C.
(3) C.
(4) C.
(5) C.
(6) C.
(7) C.
(8) C.
(9) C
8 Control specimens.
12º 35' aft 4º 10' all the 8 controls with slight geotropic curvature — The 9 with caustic quite straight.
4º 50 5º P.m. after 8º 35' The caustic ones in same state— Black tips not above 1/2 mm.
The controls are not greatly geotropic it would have been better perhaps if they had been immersed— yet certainly a considerable contrast. The radicles with caustic have grown greatly but were not measured for want of time.
26' 8º a.m. There is now no marked difference in the state of the 2 Cots. after 24 h. Result not very satisfactory— Chiefly owing to radicles not being strongly geotropic in air or water
Seem to have got power of reversing
[5v]
2.53 [÷] 7 [=] .361 inch long |
5.5 [÷] 7 [=] .785 say.79 |
14.0.2 [÷] 7 [=] 002 2.0 inches |
1.15 [+] 5.5 [+] 5.5 [+] 1..8.7 [=] 14.02
'55
, 5.5
14 inches
14.0.2
5.5
2.53
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July 4th 1879 7º 50 a.m. Cucurbita ovifera Radicle with caustic laid Horizontally on loose peat & covered over with same, little pressed.
Geotropism & tips Cauterised on all sides —Length measured from end of radicle to end of seed-coats: Kept on Chimney piece. Temp. 75º-76º F
(N.B (1) to (2) length of radicle to end of seed- ct coat when touched: (3) at 4º 45' P.m aft 9 h on 4th. — (4) length on the 5th at 8º 30' a.m aft 24ºh 40')
(1) caustic ⨀1 ⨀2 ⨀3 4º 45' sl tip slightly geotropic — only very minute very pale brown mark
5th 8 .30' a.m. End for 20 m.m rectangularly geotropic— grown greatly (but not measured from commencement)
(2) C. ⨀1 ⨀2 ⨀3 — ⨀4 4º 45' not in least geotropic— turned a little upwards— Black point 1/2 mm
(✔) 5' 8º 30. am almost horizontal enormously grown. see (4).
(3) C. ⨀1 ⨀2 ⨀3 — ⨀4 4º 45' not in least geotropic — Black mark barely 1/2 mm
(✔) 5th 8º 30' am a little tortuous & rather up-turned— enormously grown. (4)
(4) C. ⨀1 ⨀2 ⨀3 — ⨀ (4) 4º 45' not in least geotropic— Pale brown mark — less than 1/2 mm
(✔) 5th 8º 30' a.m.— Horizontal see (4) for growth
(5) C. ⨀1 ⨀2 ⨀3 — ⨀4 4º 50' decidedly geotropic— brown mark hardly visible only on extreme apex
(✔) 5th 8º 30' rectangularly geotropic for 30 mm.— see 4 for growth since the commencement.
(6) C. ⨀1 ⨀2 ⨀3 — ⨀ (4) 4º 50 no trace of geotropic— Blackish mark 1/2 mm
(✔) 5th 8º 30'— quite horizontal slightly tortuous — see (4) for growth
(7) C. ⨀1 ⨀2 ⨀3 — ⨀4 4º 50 no trace of G
(✔) 5' 8º 30' quite Horizontal see (4) for growth
(8) C. ⨀1 ⨀2 ⨀3 — ⨀ (4) 4º 55' very slightly geotropic.— Black mark very faint, & very small
✔5th 8º 30' geotropic rectangularly for a portion 25. mm. in length— See for growth from commencement see 4
(N.B. The radicles when old, as formerly seen, become very slightly geotropic
(15 Control specimens laid in same manner & at same time.) (over
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4th 5º P.m.— on the 4th Of the 15 control, 8 either rectangularly bent down, or at least as much as 45º. — The other 7 all slightly geotropic
(Also 6 laid in same manner horizontally within Peat with barely 1 mm. of tips cut off rectangularly (not measured) abov about the same length or shorter than other specimens). 5º P.m. not a trace of Geotropism. — quite straight)
(July 5' 8º 45' a.m. These 6 have now grown enormously in length & not in the least geotropic have all gone under the very loose peat; quite Horizontally & hardly tortuous at all. They are now between 40 & 50 mm. in length & nearly some quite as long as those touched with caustic.)
(4th 12º 50 P.m just past noon aft 5º — All the controls Control specimens 15 in number more or less geotropic some nearly rectangularly — Only 1 of the cauterised caustic specimen & none of those with apices cut off. geotropic
(July 5th 8º. 45' a.m all 15 controls now rectangularly geotropic & deeply deeply buried in earth the Peat — length of radicle from 45' to 45 58 mm very little or hardly at all longer on average, as judged by eye, than the caustic cauterised specimens.)
51 1/2 m.m. = 2.05
58 [-] 45 [=] 13 45 [+] 6 1/2 [=] 51 1/2.
Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)
File last updated 29 December, 2025