Scottish surgeon and botanist from Glasgow, the son of Prof. Thomas Thomson, mineralogist and Regius Professor of Chemistry at the University of Glasgow. He trained as a surgeon at Glasgow University, studying botany under W.J. Hooker, and went to India to join the Bengal army. There he accompanied W.J. Hooker's son, J.D. Hooker on his Himalayan expeditions (1847-1851) to India and Tibet (Xizang), the specimens of which were incorporated into Hooker's Herbarium Indiae Orientalis. Thomson subsequently became Superintendent of the Calcutta Botanic Garden (1854-1861) and published on the Indian flora with Hooker. Allium thomsonii Baker, Rhododendron thomsonii Hook. f. and Strobilanthes thomsonii T. Anderson are some of the many Himalayan plants named in his honour. Over 6,000 specimens were donated to BM (1855-1861) but many original cryptogamic specimens were additionally transferred from K to BM after 1961 under the terms of the Morton Agreement.