RECORD: Darwin, C. R. [1875]. Draft of The Protection of Leaves from water / Proof sheet of Cross and self fertilization, pp. 102-3. CUL-DAR66.42-43. 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 volume CUL-DAR66 contains notes on 'bloom'. Francis Darwin explained: "His researches into the meaning of the 'bloom,' or waxy coating found on many leaves, was one of those inquiries which remained unfinished at the time of his death. He amassed a quantity of notes on the subject". LL3: 339. See an Introduction to these folders by Christine Chua & John van Wyhe.
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On "The Protection of Leaves from Water by Ch Darwin
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[Insertion in another hand:] (1875)
The leaves of In a large majority of plants, at least in this country, the leaves are thoroughly wetted during heavy rain & it is to be we may presume that this does not injure them. With some sp. the surface is protected by a thick clothing of hairs, which entangle the air so that when a leaf is immersed in water it appears coated with silver & when taken out is the surface quite dry. —
— Example artichoke.
Such woolly covering is very common with plants on high mountain — Alps, New Zealand, Arctic & Himalaya (Hooker) Arctic regions?? & the view commonly held is probably the correct one that such covering serves as a protection against cold & not water.
Some leaves like Pinus laurus are highly protected, & though they are slightly wetted by heavy rain, yet a slight shaking as by wind soon free them — give my experiment, rubbing with chalk.
Again not a few plants have their leaves protected by a thin [illeg] layer of wax, & when seen as on my daily [illeg] with cabbage & sea kale to keep off water— like globules of quick-silver. — This bloom may occur on fruit. — Leguminosæ— grasses — Many water plants & several other monocotyledonous plants → Ferns— Eucalypti. some Conifers &c.
[1v]
[Proof sheet of Cross and self fertilization, p. 102, published p. 201.]
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Certain movements of plants also appear to me as if they were seemed adapted to prevent water lodging on the leaves & this had one idea has led me to investigate subject as far as I have been able. As all the plant which through [illeg] go to sleep at night, I have found it necessary to attend also to this subject. — The first point to ascertain was whether the loss removal of the bloom or Pruina (?) — or waxy secretion wd injure leaves in any fruit or leaves in any degree.—
First for fruits — wd not be eaten & disseminated.
wd seeds be eaten.
Then experiment on leaves.— (begin with the details of any movements)
[43v]
[Proof sheet of Cross and self fertilization, p. 103, published pp. 203-4.]
Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)
File last updated 5 July, 2023