The date is established by the relationship between this letter and the letters from W. E. Darwin, 1 August 1862 and 2 August [1862] (Correspondence vol. 10). This letter is probably a continuation of the incomplete letter from W. E. Darwin, 1 August 1862 (Correspondence vol. 10).

William’s horse had fallen when he was out collecting plants (see Correspondence vol. 10, letter from W. E. Darwin, 1 August 1862).

Francis and George Howard Darwin were going to stay with William in Southampton; they were due to arrive on 1 August (letter from Emma Darwin to W. E. Darwin, [late July 1862] (DAR 219.1: 59)). However, they did not arrive until 2 August (see Correspondence vol. 10, letter from G. H. Darwin, [after 5 August 1862] and n. 3).

By ‘MP’, William means ‘middle-pistilled’ (see Correspondence vol. 10, letter from W. E. Darwin, 1 August 1862). William was helping CD investigate the manner of fertilisation of three forms of Lythrum salicaria, which differed in having pistils with styles of different lengths. CD termed these long-styled, middle-styled, and short-styled; he published the results of his crossing experiments in 1864 in ‘Three forms of Lythrum salicaria’.

Emma had previously written to say that Jessie Brodie, who had been William and Anne Elizabeth Darwin’s nurse until 1851, would arrive towards the end of Francis and George’s stay (letter from Emma Darwin to W. E. Darwin, [July 1862?] (DAR 219.1: 47)). In a letter to William of [late July 1862] (DAR 219.1: 59), Emma Darwin reported that Susan Elizabeth Darwin, CD’s sister, had ‘a great fancy for larking down to Southampton with the boys’, and suggested that William should write to invite her. While in Southampton, Susan was to stay with Mary Pratt, the wife of a lodging-house keeper in Southampton.