Edith L. Stephens, botanist, was the daughter of Michael Stephens, chief locomotive superintendent of the Cape Government Railways, and his wife Annie Hoskyn. She matriculated at the Rustenburg Girls' High School in Rondebosch, Cape Town, in 1901. In 1904 she entered the South African College, Cape Town, and later that year passed the intermediate examination for the Bachelor of Arts (BA) degree of the University of the Cape of Good Hope. Continuing her studies at the college she was joint winner of the Gold Medal in Science for 1906 and that same year completed the BA degree with honours in botany (awarded by the University of the Cape of Good Hope). Early in 1907 she was awarded the 1881 Exhibition Science Research Scholarship by the South African College and entered Newnham College, University of Cambridge, to continue her studies in botany. The next year she published "A preliminary note on the embryo-sac and embryo of certain Penaeaceae" in the Annals of Botany, based on research begun at the South African College. Her studies did not lead to a qualification, as the University of Cambridge did not award degrees to women at that time. She was, however, elected a Fellow of the Linnean Society of London.
Stephens returned to South Africa around 1911. During the first half of 1913 she was a temporary lecturer in botany at the South African College, but in June that year succeeded W.T. Saxton* as lecturer in botany. She remained in the Department of Botany when the college became the University of Cape Town in 1918, until her retirement in 1940. Thereafter she continued as honorary reader in systematic botany (cryptogams) at the university's Bolus Herbarium until her death in 1966. Late in 1916, following the death of Professor H.H.W. Pearson*, she was appointed acting head of the Botany Department until his successor arrived in 1919.
Stephens published the following papers: "The structure and development of the haustorium of Striga lutea" (Annals of Botany, 1912), "Note on the anatomy of Striga lutea" (Ibid, 1912), "The Capparidaceae and Polygalaceae of the Percy Sladen Memorial Expeditions" (Annals of the South African Museum, 1912), "A new species of Haematoxylon (Leguminosae-Caesalpineae) from Great Namaqualand" (Transactions of the Royal Society of South Africa, 1913), "Contributions to our knowledge of the freshwater algae of Africa. 3. Freshwater algae (exclusive of diatoms), mainly from the Transkei Territories" (as co-author with F.E. Fritsch, Ibid, 1921), "Carnivorous plants of the Cape Peninsula" (Journal of the Botanical Society of South Africa, 1923), "Notes on the acquatic flora of South Africa" (South African Journal of Science, 1924), "New and noteworthy South African Charophyta" (as co-author with J. Groves, Transactions of the Royal Society of South Africa, 1926, 1934), "A new sundew, Drosera regia (Stephens), from the Cape Peninsula" (Ibid, 1926), "Notes on three South African terrestrial Utricularieae" (Journal of South African Botany, 1938), and "Notes on Gethyllis" (Herbertia, 1939). In 1915 she worked out the families Pennaeaceae and Geissolomaceae for the Flora Capensis (Vol. 5(2), pp. 81-100). She also contributed to The botanical features of the south-western Cape Province (Cape Town, 1929) by R.S. Adamson and others.
Stephens was an excellent field naturalist who made a special study of the fresh water algae and other acquatic plants in the temporary vleis on the Cape Flats, and later of local fungi. Many of her specimens were sent to specialists in Europe for study. The story is told that once when working in a vlei near Valkenburg psychiatric hospital in her rather eccentric outdoor attire she was taken into custody by an official who thought she was an escaped patient. It took several phone calls and much argument before she was identified and released. Her knowledge of local mushrooms was often used to assist amateur mushroom collectors and led her to publish two popular booklets on the subject: Some South African edible fungi and Some South African poisonous and inedible fungi. Both books were illustrated by Mary M. Kidd, and both were published in Cape Town in 1953. At the time of her death she was working on a more comprehensive treatise on the same subject.
Stephens was one of the three persons who founded the Cape Natural History Club in 1922. She served as its first president for a year, was elected an honorary life member, and edited its journal, The Cape Naturalist, from its foundation in 1934 to 1939. In 1917 she became a life member of the South African Association for the Advancement of Science. By 1917 she was a member also of the Royal Society of South Africa and in 1929 was elected one of its Fellows. In 1922 she became a member of the South African Biological Society and for some time served on its council. She was a member also of the Limnological Society of South Africa.
One of her major interests was the restoration of the flora of the Cape Flats, much of which had been destroyed by the Australian wattle. In 1957 she received the Cape Tercentenary Foundation award for the conservation of the fauna and flora of the Cape Province. She used the money to buy a four hectare vlei near Philippi on the Cape Flats, which she named Isoetis Vlei because the rare and primitive semi-acquatic plant of the fern family, Isoetis capensis, flourished there. She presented the property to the National Botanic Gardens at Kirstenbosch to ensure its preservation. It was named the Edith Stephens Cape Flats Floral Reserve. Specimens collected by her went to the Bolus Herbarium, the National Collection of Fungi of the Plant Protection Research Institute in Pretoria, and the Compton Herbarium of the National Botanical Institute in Cape Town.