Thomas Cooper, horticulturalist and plant collector, was the father-in-law of the botanist N.E. Brown*. He was originally a cabinet maker in London, but became a plant collector for W.Wilson Saunders, a nursery owner at Reigate, Surrey, who had one of the finest private gardens in England. In 1859 Cooper came to South Africa on behalf of Saunders and the Royal Horticultural Society to collect both live plants for Saunders's nursery and dried plants for various herbaria. Before his departure W.J. Burchell* presented him with a copy of the map published in his Travels in 1822.
Cooper arrived in Cape Town on 12 June 1859 and after a stay of more than three years returned to England from Durban in September 1862. He first collected around Cape Town, and from October 1859 around Worcester. In April 1860 he went to Port Elizabeth and collected at various places up to Grahamstown. At the end of June he left that city and proceeded on a long, meandering journey during which he visited King William's Town, Cathcart, Queenstown, Alice, Fort Beaufort, Bedford, Cradock, Burgersdorp, and Aliwal North, which he reached in March 1861. From there he continued on to the Bethseda Mission Station (now Maphutsaneng) in Lesotho, and collected at Morija and Thaba Bosigo. He collected several hundred specimens in Lesotho, including some ferns, but surprisingly no grasses. Nontheless he was the first plant collector of importance in the territory, even though he was there during the winter months. He reached Harrismith in the Free State in September 1861. From there he proceeded via Ladysmith, Karkloof and Pietermaritzburg to Durban, where he arrived on 22 August 1862. He is regarded as an important early collector in KwaZulu-Natal.
Cooper was an active collector and shipped many cases of natural history material back to England. Included were many live plants to be cultivated for the first time, seeds, and herbarium specimens. He was particularly interested in succulents and the new species collected by him included eight species of Aloe. His name is commemorated in many species, including Euphorbia cooperi, Crassula cooperi, Disa cooperi, Aloe cooperi, Scilla cooperi, Sutera cooperi, and Stultitia cooperi. Some of the plants grown in England after his return were described for the Flora Capensis by his son-in-law, Brown. His collections also included animal horns, shells, insects and reptiles. Most of his herbarium material is at Kew Gardens. However, much is in Zurich, probably because he sold it when Saunders, who owed him money, went bankrupt.
Cooper collected for Saunders in many countries. He lived to the ripe old age of 97. During the last 20 years of his life he resided in the home of his daughter and son-in-law at Kew, a suburb of London.