This letter was published in Correspondence vol. 21 from a copy at CUL; the original was later found at the Royal Botanic Gardens, Kew. CD had asked Francis Darwin to ask Hooker for another species of Desmodium for his work on movement of plants (see letter to Francis Darwin, 10 October 1873 and nn. 8 and 10). George Rollisson was in charge of Springfield Nursery in Upper Tooting, Surrey (Gardeners’ Chronicle (1880) 1: 23). Desmodium polycarpum (now Desmodium heterocarpon) has three leaflets. ‘D. polycarpus violaceus’ has not been identified.

Desmodium gyrans is the telegraph plant, now Codariocalyx motorius.

CD probably refers to John Hutton Balfour of the Royal Botanic Garden in Edinburgh. He discussed Neptunia oleracea (a synonym of N. prostrata) in Movement in plants, pp. 128, 374, 402–3.