RECORD: Darwin, C. R. 1866.08.17. Apios tuberosa. CUL-DAR49.111. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 1.2022. 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-DAR49 contains notes for Natural selection chap. 3 on 'On...organic beings occasionally crossing' or dichogamy.


[111]

Aug 17th 66 Apios tuberosa - Keel a tube with edge coherent at end, curved into a sickle-formed, with extremity enlarged & firmly lodged in fitting cavity at upper margin of standard - Lateral or wing petals drooping & rather shrunk - Bee stands either on them or on summit of standard & when weather is hot small push frees keel from its lodgment & then it curls down & in each stigma & stamen are largely protruded - stigma conical surrounded by brushes & after the spout protrusion rests on its own lower part, forming a circle. Apparently does not receive own pollen, but it & anther wd be brushed by Bee entering either side for nectar, of which I saw none, but plant unhealthy. Pollen scanty. I do not believe without aid end of Keel wd even be freed from lodgment. When free extremity of Keel splits open, allowing egress of R. Organs

(Over)

 

[111v]

Asa Gray in Flora says Keel-petal becomes ultimately twisted - Is this after or before impregnation?

I have ascertained positively that Keel in protected flowers does not free itself -

4 fl. white Thread fertilised, but pollen very scanty

3 marked by bundle of black thread, with stigma scantly freed from tube

 

(All flowers dropped off Plant unhealthy)


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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 25 September, 2022