Ɛpsilon

To Adolf Ernst   4 April 1880

Down, | Beckenham, Kent. | Railway Station | Orpington. S. E. R.

April 4 | 1880

Dear Sir

Your excellent letter has interested me much.1 I have had much pleasure in ordering the two books to be sent to you.2 It grieves me that you have so little time for observing, as I feel sure that you would make many interesting discoveries. That seems to me a good idea about punching out the glands of Passiflora.3 I wish you could get pollen of Abutilona Striatum from some other country or district as I should expect that with its aid you could raise vigorous seedlings from the weak plants long cultivated near Caracas.4 I still think, that if you can find the requisite time that it would be well worth while to test the fertility of illegitimate offspring from heterostyled plants. Should you hereafter be able to make any observations on the frequency of bloom-covered leaves on the dry plains I should be particularly glad to hear.5 I entirely agree with what you say about M. Bonnier’s work which has now been published separately.6 I know nothing about Triplaris.7

Pray forgive brevity, as I have many letters to write My dear Sir | Yours faithfully | Charles Darwin

P.S. Is not the Turnera defended by its ants against leaf-cutting ants or other enemies?8

LS(A)

2
See letter from Adolf Ernst, 29 February 1880 and n. 14. CD sent copies of Coral reefs 2d ed. and Geological observations 2d ed.
3
In his letter of 29 February 1880, Ernst had proposed removing the extrafloral nectaries on leaves of Passiflora biflora (twoflower passion-flower) to test whether fertilisation without insect aid was possible.
4
Abutilon striatum (a synonym of A. pictum) is painted Indian mallow. Ernst reported that the plant, which had been introduced as a single specimen from Peru, never produced fruit and seemed to be dying out.
5
Ernst wrote that he had not recently visited the interior plains of Venezuela, where CD hoped he would find plants with leaves covered in bloom, a waxy secretion (see letter from Adolf Ernst, 29 February 1880 and nn. 2 and 3).
6
Bonnier 1879b (see letter from Adolf Ernst, 29 February 1880 and n. 7); the separately published version was Bonnier 1879a. CD had earlier commented that Gaston Bonnier seemed to deny that nectaries were ever modified to encourage the visits of insects (see Correspondence vol. 27, letter to W. J. Behrens, 10 November 1879).
7
Ernst had described the relationship between ants inhabiting Triplaris americana, a species of knotweed, and scale insects (see letter from Adolf Ernst, 29 February 1880 and n. 10).
8
Ernst had described the extra-floral nectaries at the base of leaves of Turnera ulmifolia and observed large numbers of ants on the leaves (see letter from Adolf Ernst, 29 February 1880 and nn. 5 and 6). Fritz Müller had informed CD that ants that lived in plants of the genus Cecropia (embauba or trumpet tree) prevented herbivorous insects from attacking these trees (see Correspondence vol. 22, letter from Fritz Müller, 20 April [1874]).

Manuscript Alterations and Comments

3.1 P.S. … enemies? 3.2] in CD’s hand

Please cite as “DCP-LETT-12561,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-12561