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Darwin Correspondence Project

From Robert Thomson   24 July 1864

Botanic Garden | Golden Spring P.O. | Jamaica

24 July 1864


Being informed by Mr. Wilson1 about a year ago that you were desirous of ascertaining if any Insects visit the flower of Melastomaths,2 I accordingly give you the result of my observations on one species, a specimen of which, together with several of the insects, I enclose to you.

It may here be desirable for me to state that I was appointed Mr Wilson’s assistant by Sir W. Hooker3 in Kew Garden two years ago. I am engaged in the formation of a new Botanic Garden.4

There is not the slightest attempt at botanical arrangement, or the representation of the Flora of the Island. The chief object of the garden is as a Nursery for the propogation of useful and ornamental plants for gratuitous distribution; at the same time ornamental gardening is not disregarded

I am of oponion that if a selected collection of the Flora of the Island which is as yet very imperfectly developed, were systematically represented, the garden would acquire an important position, and be of great and general service to the scientific world.

I look forward with a little more time and an increased knowledge of Botany at command, to devote myself to the development of the Flora of the Island

Observations on the species above referred to:—

I have repeatedly examined with care for the last few months, and have without a single exception found the Insects occupied in almost every flower around the base of the style, and in the cavity formed by the calyx, whence the object in which the Insect is in search of, is obviously obtained. Minute radiate hairs are appended to the organs with which the Insects are in contact.

Pollen masses are also copiously strewed in their midst.

The anther previous to the full expansion of the flower (if fully expanded the pollen is discharged from its cell) are densely filled with pollen. When the loculament in a special condition is slightly pressed the pollen issues from the apical pore; the mass appearing to the naked eye amorphous particles, but under the microscope the pollen are exceedingly minute ovate cohesive granules. If the part magnified happens to be a single layer they are aggregated so closely together that there is not the smallest apparent interstice perceptible: thereby a beautiful example of simple cellular tissue

I remain | Sir | Your most humble servant | Robert Thomson

The insects are attached to the under surface of the fragments of leaves enclosed with Cotton


Nathaniel Wilson.
CD had sent queries to many gardeners and botanists for information on the habits of insects visiting flowers of the family Melastomataceae (see letter from A. R. Wallace, 2 January 1864 and n. 13).
William Jackson Hooker.
Thomson had been appointed an assistant gardener to Wilson in 1862. Wilson, who was curator of the oldest botanical garden in Jamaica, located at Bath, was also overseeing the establishment of a new botanical garden at Castleton, nineteen miles north of Kingston on the road to Annotto Bay. Land for the garden at Castleton had been purchased in 1857. Thomson was stationed at Castleton and, under Wilson’s direction, helped to establish the new garden (Morris 1898, pp. 137–44).


Morris, Daniel. 1898. Report on the economic resources of the West Indies. Royal Gardens, Kew. Bulletin of Miscellaneous Information. Additional series 1.


Observations on insects visiting Melastomataceae.

Letter details

Letter no.
Robert Thomson
Charles Robert Darwin
Sent from
Botanic Garden, Jamaica
Source of text
DAR 178: 117
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 4574,” accessed on 18 January 2022,

Also published in The Correspondence of Charles Darwin, vol. 12