Has been observing the movements of leaves and cotyledons; sleep movements are exaggerated circumnutation. Reports some odd observations on movement in Oxalis species.
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The Charles Darwin Collection
The Darwin Correspondence Project is publishing letters written by and to the naturalist Charles Darwin (1809–1882). Complete transcripts of letters are being made available through the Project’s website (www.darwinproject.ac.uk) after publication in the ongoing print edition of The Correspondence of Charles Darwin (Cambridge University Press 1985–). Metadata and summaries of all known letters (c. 15,000) appear in Ɛpsilon, and the full texts of available letters can also be searched, with links to the full texts.
Has been observing the movements of leaves and cotyledons; sleep movements are exaggerated circumnutation. Reports some odd observations on movement in Oxalis species.
Can send FD twisted branches of some climbing plants if he wishes.
Asks questions related to movement in plants. The cotyledons of Oxalis offer a promising field for study.
Wonders why Julius von Sachs thinks bloom is a protection against insects.
Encloses notes on the cotyledons of Oxalis species.
Sleep of Porlieria hygrometrica seems independent of light.
Will have lots of time for oats. W. F. P. Pfeffer’s point is that there is no growth in sleepers with joints. A. F. Batalin says there is a slight growth.
[Dated Saturday 28th by FD.]
Will dispatch the best twisted stems he can find.
Considers the role of the pulvinus in leaf movement.
JIR’s brother writes from India in support of the protective function of plant sensitivity.
Suggests FD call on Carl Semper.
Inquires about Porlieria: Do the leaves shut to check evaporation? Does it appear silver under water?
Explains how he thinks the pulvinus acts; wishes FD would investigate the point.
Has a magnificent bush of Porlieria. There is no vestige of bloom; CD will test for sleep movements. Reports successful experiments on temperature-induced sensitivity of radicles.
He has been talking to Julius von Sachs about sleeping plants that move with and without growth.
Describes sleep movements in Porlieria and his experiments on movements of radicles.
Thalia flowers have interesting mechanism to ensure cross-fertilisation.
Sleep in Porlieria studied.
Oats begin germinating.
Chlorophyll development in oat seedling.
Lists the sleeping plants he has seen.
Julius Sachs thinks Hugo de Vries has not cleared up everything [about climbing plants]. But Sachs has not worked on the mechanical problem.
Asks for list of families of sleeping plants. Believes sleep is merely modified circumnutation at a particular time of day.
Porlieria has had no water for some time but shows no sign of flagging.
Describes the response of Thalia flowers to touch.
More sleepers from green-house.
Julius Sachs’s view of climbing plants: he distinguishes between nutation to find a support and growth after support is found.
Discusses sleep movements of Porlieria.
Has read an abstract of Julius Wiesner on heliotropism and geotropism ["Die heliotropischen Erscheinungen im Pflanzenreiche", Anz. Kais. Akad. Wiss. Wien 15 (1878): 137–40] which seems important but is puzzling.
Gives details of his observations on climbing plants with reference to comments by Julius Sachs.
Has offered Carl Semper the writing machine.
Speculates on the mechanism of movement in plants and their reception of and response to stimuli.
Is forwarding the writing machine to Carl Semper.
Is glad FD has taken up his old friends, the twiners.
Hopes to get heliotropic aerial roots from J. D. Hooker. Asks FD to find out whether any moulds or roots are apheliotropic. Is puzzled by heliotropism in subterranean roots.
Experiments on effects of removing "bloom" from leaves and fruit.
Comments on function of bloom.
Describes the effect of water shortage on sleep movements in Porlieria.
Sachs jumps to the conclusion twiners and tendrils are similar from the Menispermum that twined without a stick. Akebia grows down a stick; not only the free end is involved.
Sleeping plants.