RECORD: Darwin, C. R. 1867-1869.09.07. Thunbergia alata. CUL-DAR79.72-74. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 3.2023. 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-DAR 76-79 contain material for Darwin's book Cross and self fertilisation (1876).


(62

1867

Thunbergia alata. The plants early in season produced hardly any pollen; & then it increased & very few flower set when artificially fertilised; late in season numerous flower set most freely & spontaneously. (Hence possibly did not really cross them)

[table not transcribed] Seed put on Damp Sand. Decr. 24th

The self plants when very young looked miserable; but now April 3 /68/ when the plants are about 3 inches in height, they are nearly equal in all ways.)

(62 A

Thunbergia — Some plants about a foot high & made a few turns round sticks.

Pot I. II 3 self considerably taller— I neglected to record, but believe that self- flowered first. (May 15th Crossed 20 inches, self 45 inches!)

July 3 Crossed 3. 8 1/2 Self 5 ft 11 in

IV. crossed highest— May 12 flowered first one of the self- died; but I neglected to measure it, but was shorter than crossed. The other self soon stopped growing, whilst both crossed grew to great height (1 self)

V. self- a little the highest (Crossed & selfs flowered at same time.)

crossed 6. 10 1/4 — 6—4. Self 7. 3 1/4 6. 8 1/4

VI. selfs a little the highest.

The self-plant flowered before crossed.

Crossed 6. 10 1/4 — Self- 7. 3 1/4

So in all cases the self the tallest!!!

8 pairs

(62 B

Thunbergia— 1868 12 [+] 14 [=] 26

Lettington crossed 12 flowers, but they produced only 4 capsules with only 5 seed altogether (viz 2, 1, 1, 1)

He self-fertilised 8 fl & & these produced 4 capsules with altogether 10 seed (viz 3, 4, 1, 2) Subsequently these plants produced a good many spont, self-fertilised.—

So self-fertilising much the more efficient! Nearly the same result last year!!

I succeed in on raising in Pot I at same time 2 crossed & 2 self Plants — & in Pot II one of each kind.

(March 14 1869 — The crossed in Pots look finest, plants are inch or two high.)

(May 16. 1869.

Pot I. first Plant: crossed Plants 1/2 inch higher, than self second Plant; the self 5 inches higher than crossed a crossed self plant flowered first in this pot

Pot. II The one crossed plant 6 1/2 higher than self.— But in this Pot at first the self was ahead of the crossed.—. A crossed flowered first in the Pot

Sept 7. 1869 Same two Pots, Plants now stopped growing

 

Pot I

Crossed

inches

38

44 4/8

Self

 

54

43

Pot II

73

55 4/8

 

155.5

152.5


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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 October, 2023