Miss Magdaline (or Magdalen, Magdalena) Dalgairns was a daughter of the 1820 settler Charles Dalgairns, a farmer. She and her older sister Agnes maintained a small school in Knysna around the middle of the 19th century. She collected ferns in the neighbourhood around 1856. In 1880 she donated her herbarium of 226 species of plants from the Knysna district to the South African Museum. The fern species Lomaria dalgairnsiae was named in her honour in the 1875 revision of C.W. Ludwig Pappe* and R.W. Rawson's* Revised list of the ferns of South Africa.