Sir Thomas Gery Cullum, 7th Baronet (30 November 1741 – 8 September 1831) was a medical doctor educated at London Charterhouse and Trinity College, Cambridge, and who later practised surgery at Bury St. Edmunds, Suffolk, where he served as an alderman and DL for Suffolk. Cullum was the son of Sir John Cullum, 5th Baronet, of Hardwick House, Hardwick, Suffolk.
Sir John Cullum, 6th Baronet (1733–1785), the brother of Thomas Gery Cullum, was known as the 'historian of Hawstead'. His brother and successor Thomas shared his literary inclinations, and became 7th Baronet in 1785. He was a well-regarded writer on science and on botany and a fellow of the Royal Society, Society of Antiquaries of London and of the Linnaean Society.
Cullum's credentials as a scholar were such that he was recommended as a fellow of the Royal Society in January 1787 along with his fellow scholar James Smithson, for whom the later Smithsonian Institution would be named. Cullum also served as Bath King of Arms from 1771 to 1800. He was succeeded as Bath King of Arms by his son John Palmer Cullum, Esq, who served from 1800–1829, which meant that between them the pair served for nearly 60 years.
Perhaps the highest compliment paid to Cullum was that from Sir James Edward Smith, noted English botanist and founder of the Linnaean Society. Smith dedicated his English Flora of 1824 to Cullum thus: "To Sir Thomas Gery Cullum, Bart., whose knowledge and love of natural science entitle him to the respect of all who follow the same pursuit, this work is inscribed in grateful and affectionate remembrance by the Author." Smith's publications had followed a privately printed flora by Cullum, Floræ Anglicæ Specimen imperfectum et ineditum, 1774, which was based on the Linnean system of classification