Henry Augustus Melle, agrostologist, was the son of Dr George James McCartney (or McCarthy) Melle* and his wife Anna Elizabeth Susanna, born van Niekerk. He attended the South African College School in Cape Town and Brasenose College, University of Oxford, where he obtained a first class honours degree in agricultural science. He was employed as an agricultural assistant at the Vryburg Experiment Station of the Department of Agriculture and while there contributed an article titled 'Lucerne (Medicago sativa): From the seed-bed to the market' to the Agricultural Journal of the Union of South Africa (1913, Vol. 6, p. 950). During World War I (1914-1918) he served with the artillery. After the war he returned to the Department of Agriculture and was placed in charge of the Groenkloof Botanic Station in Pretoria. With the encouragement of Dr I.B. Pole Evans* he became interested in agrostology (the study of grasses) and wrote Agricultural grasses and their culture (Department of Agriculture, 1918). He and S.M. Stent* later published articles on Sudan grass (Sorghum sudanense), Rhodes grass (Chloris gayana) and Star grass (Cynodon plectostachyum) in the Journal of the Department of Agriculture of South Africa (1921, Vol. 2, pp. 425-433; Vol. 3, pp. 136-141 and pp. 271-276). He became a member of the South African Biological Society in 1920.
Melle resigned in the mid nineteen-twenties to farm in the Pretoria district. Later he was employed in the Department of Native Affairs and became deputy director of Native Agriculture. On 8 July 1922 in Pretoria he married Grace Jeanette van Boeschoten, with whom he had two daughters. The species Acacia mellei was named after him. Botanical specimens collected by him went to the National Herbarium in Pretoria.