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Darwin Correspondence Project

From William Masters   [after 7 April 1860]1

Facts and inferences obtained from the observation of the varieties of the Sweet Pea under culture for more than a quarter of a century—

—The following varieties of the Sweet Pea have been largely cultivated by me—viz—White Painted Lady—Scarlet—Purple—Black and Striped or Powdered (Blotched)

During more than 20 years the White never changed at all—

The Painted Lady never became white or indeed presented any great amount of change—but when a change was manifested it was as an advance in color—the pink or scarlet variety as it is sometimes called, being produced: And here a marked change occurred—the habit of the plant was altered and the form of the “alæ” or lateral petals was slightly changed— The advance having begun; transition now became more frequent, the general tendency still being shown in the increasing depth of color in the petals so that the purple variety was produced. This occurred so frequently that annual selection became necessary to keep the two sorts (pink and purple) distinct—2

The purple and black varieties seem to bring up the series—they are lighter or darker varieties of the same form and the black so liable to revert to purple that I ceased to grow them as distinct kinds—

In no one instance do I remember to have seen a white or Painted Lady become purple but the pink or scarlet variety presented this change by no means infrequently.

The other variety—the striped or powdered, I obtained from France— Here the flowers instead of having their colors distinct had purple blotches on a grey ground.— This was the most difficult variety of any to keep “true” its tendency being to return to the black variety, but I have no doubt but that by selection, in a few generations, I should have had both pure white and pure black from the same stock—3

From these observations I infer that all Sweet Peas were originally white, and as variation is induced so the vigor of the Variety becomes manifest in the intensity of its color, hence the natural deepening of color till we arrive at the last—the striped or powdered variety.— This latter I believe to be a cross between the white and the deep purple and hence its deviation from the other kinds enumerated, all of which I believe to be natural variations produced without hybridization—

That “Natural Selection” is the cause of such general uniformity I cannot doubt for each variety is fertilized by its own pollen although surrounded on all sides by the flowers of the other varieties.

In the whole course of these observations not one variation was produced worthy of selection as constituting a new sub tribe

William Masters

CD annotations

1.2 Painted Lady] underl brown crayon
1.2 Purple] underl brown crayon
3.3 pink or scarlet variety] underl brown crayon
3.6 shown … produced. 3.7] scored brown crayon
6.3 This was … “true”] scored brown crayon


Dated by the relationship to the letters to M. T. Masters, 7 April [1860] and 13 April [1860]. The draft of CD’s reply to this letter is headed ‘April 13 1860    to Mr Masters’ (DAR 77: 27). See letter to M. T. Masters, 13 April [1860] and CD note.
The letter is a response to a query posed by CD in his letter to M. T. Masters, 7 April [1860].


Facts and inferences relating to different varieties of sweetpeas.

Letter details

Letter no.
William Masters
Charles Robert Darwin
Sent from
Source of text
DAR 77: 39–40
Physical description
memS 3pp †

Please cite as

Darwin Correspondence Project, “Letter no. 2622,” accessed on 22 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 8