Thwaites

Thwaites started out as an accountant and in his spare time devoted himself to botany, particularly cryptogams and algae, which he observed under a microscope. In 1839 he became Secretary of the Botanical Society of London for Bristol. He showed that diatoms are plants and not animals, which earned him a reputation. J. François Camille Montagne dedicated the naming of the algae genus Thwaitesia to him in 1845. In 1846 he became Lecturer in Botany at the Bristol School of Pharmacy and then at the Bristol Medical School. An application for a chair in natural history at one of the newly founded Queen's Colleges in Ireland was unsuccessful. In 1849 he succeeded the late George Gardner as head of the Botanical Gardens in Peradeniya (first as superintendent, from 1857 as director). In 1880 he gave up the post for health reasons. His successor was Henry Trimen.

He wrote a monograph on the plants of Ceylon and also dealt with flowering plants and entomology and in Ceylon with different cultivated plants. He introduced the cultivation of cinchona trees in Ceylon. He contributed to the monograph on the butterflies of Ceylon by Frederic Moore (Lepidoptera of Ceylon, 3 volumes, 1880 to 1889).

For his book on Ceylon plants he became a Fellow of the Royal Society in 1865 and received an honorary doctorate from the Leopoldina. In 1854 he became a Fellow of the Linnean Society of London. In 1878 he became Companion of the Order of St Michael and St George