RECORD: Darwin, C. R. [1878].09.06. Tropaeolum majus / Draft of Cross and self fertilisation. CUL-DAR209.7.125. (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 8.2022. 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 volumes CUL-DAR209.7-8 contain notes on heliotropism (phototropism) for Darwin's book Movement in plants (1880).


[125]

Older seedling Sept 6th (Kept dark till now)

Pot slewed round (Used)

7° 45' first dot
8. 8' to left & down
10° 21' ⨀
10. 51
11°
11. 4
11. 10
11. 13 1/2
11. 18

4° P.m to Left
4. 35 to Right parallel
4 . 45 to light
5 . 10 from light
5 . 30 an atom from light
7. 10 from light
no 3 not traced only dscrbed
circumnutate in transverse line to light

11 22 1/2
11. 27    rather straighter line than one which has been Traced /
11. 35

Used

11 . 44 Here begin to zig-zag slightly
11. 51.
12 . 18' (slower)     Here deflected from course
X    12. 50 to left at nearly 90° from previous line.
1° 1'
X 1 . 13 on & little beyond edge of Horizontal glass
1 . 28 on Vertical glass
1. 39 up to edge of glass— returned on course
1. 55 on Horizontal glass ⨀ — so I suppose circumnutating
2. 15 to Left on Hor. glass ✔
2 31' to Light ✔
2. 50 to Right ✔
3. .1 to Light ✔
3. 30 to Left

[125v]

often very closely [5 words excised]

exposed to the same conditions which as we shall hereafter is a very important circumstance— it is not at all surprising that the difference between them in the later generations should have somewhat decreased. It is on the contrary an astonishing fact, that the crossed plants should have beaten been victorious even in to a slight degree over the self-fertilised plants of the later generations.)

(29) (The much greater constitutional vigour of the crossed plants compared with the self-fertilised ones plant was proved on five occasions in various ways; namely

[Cross and self fertilisation, pp. 55-6: "When, however, we remember that the self-fertilised and crossed plants are all descended from the same mother-plant, that many of the crossed plants in each generation were related, often closely related, and that all were exposed to the same conditions, which, as we shall hereafter find, is a very important circumstance, it is not at all surprising that the difference between them should have somewhat decreased in the later generations. It is, on the contrary, an astonishing fact, that the crossed plants should have been victorious, even to a slight degree, over the self-fertilised plants of the later generations."]


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Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)

File last updated 18 December, 2025