The letter has not been found; Thiselton-Dyer had evidently written to either CD or Francis Darwin urging that Francis allow his name to be put forward for the post of examiner in the natural sciences tripos at the University of Cambridge. See also letter from J. D. Hooker, 13 March 1879.

In a letter to Thiselton-Dyer dated 13 March 1879 (Directors Correspondence English Letters COO–DEW 1866–1900 volume 83 f.230–231, Archives, Royal Botanic Gardens, Kew), Francis explained that he had received a telegraph while still in Algiers asking whether he would accept the place, but because it was unclear what the place was, he had telegraphed Cambridge University refusing it. After thanking Thiselton-Dyer for his offer to help, Francis refused on the grounds that he was not sufficiently qualified. Thiselton-Dyer’s offer evidently had been made in the now missing letter (see n. 1, above).

Mimosa is the genus of sensitive plants; most of CD’s experiments for Movement in plants were performed on M. pudica (shame plant). CD had requested and received many seeds and plants from Thiselton-Dyer since beginning his research on plant movement (see Correspondence vols. 25 and 26).