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Darwin Correspondence Project

From J. I. Rogers to Francis Darwin   29 March 1878

119, Cannon Street, | London, | E.C.

29th March 1878.

Dear Sir,

I thank you for your note and now that your father is investigating the movements of the Sensitive plant, we shall have their mysteries effectually cleared up—1 My theory about them was published a⁠⟨⁠bout⁠⟩⁠ 212 years ago in an anonym⁠⟨⁠ous⁠⟩⁠ letter I wrote the “Field”.2

The down pointing prick⁠⟨⁠les⁠⟩⁠ while rendering the visits of creeping insects difficult appeared rather to facilitate their escape.

The steady swaying motion by which Bees are shaken by the wind, is very different to the creeping contraction of the Sensitive plant, which has something uncanny about it. Though winged insects need have no fear of falling, a movement in the component parts of their foothold might cause ⁠⟨⁠them⁠⟩⁠ alarm.

If you want to get caterpillars off a plant you shake it, and they fall off, though perhaps ordinary wind may not dislodge them.

Are not Cotyledons very rarel⁠⟨⁠y⁠⟩⁠ attacked by insects & ⁠⟨⁠do⁠⟩⁠ not their depredations commence at a later stage in the plant’s growth? I have not specially watched the point, but I used to raise a great many seeds & this strikes me to have been the case, in connection with the point you mention as to the non-sensitiveness of the Cotyledons of the Sensitive ⁠⟨⁠plant⁠⟩⁠

Pray do not trouble yourself to reply to this note and Believe me to be | Yours faithfly | J. Innes. Rogers.

F. Darwin Esq. | The Down | Beck⁠⟨⁠en⁠⟩⁠ham.

Footnotes

Francis Darwin’s note has not been found; see, however, the letter from J. I. Rogers to Francis Darwin, 25 March 1878, about movement in Mimosa pudica (shame plant).
In the Field, 18 September 1875, p. 321, Rogers suggested that leaf movement in Mimosa pudica helped to protect the plant from crawling insects such as caterpillars.

Summary

JIR’s "theory" of sensitive plants published in an anonymous letter he sent to the Field 2½ years ago. Mechanisms for protection against insects in sensitive plants.

Letter details

Letter no.
DCP-LETT-11453
From
John Innes Rogers
To
Francis Darwin
Sent from
London, Cannon St, 119
Source of text
DAR 176: 197
Physical description
ALS 3pp

Please cite as

Darwin Correspondence Project, “Letter no. 11453,” accessed on 28 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-11453.xml

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