and Gilmour to represent the society in his stead. The congress appointed a special committee to consider nomenclatural issues related to cultivated plants, which became known as the Committee for the Nomenclature of Cultivated Plants (the "Stockholm Committee"), with Stearn as secretary (1950–1953). Stearn then proposed an International Code of Nomenclature for Cultivated Plants (the "Cultivated Code"), producing the first draft that day. The code was accepted in principle by the committee, conditional on its approval by a parallel committee of the International Horticultural Congress (the Horticultural Nomenclature Committee), which would next meet in London in 1952 (the "London Committee"). Later that year Stearn was also appointed secretary of the London Committee so that he now represented both organisations. The two committees then met jointly on 22–24 November 1951 at the RHS building in London to draft a final joint proposal that was published by Stearn as secretary of an editorial committee and adopted by the 13th International Horticultural Congress the following year. The resulting code was formulated as a supplement to the existing International Code of Botanical Nomenclature. Stearn introduced two important concepts, the terms "cultivar" and "grex". Cultivar, a term first proposed by L. H. Bailey in 1923, refers to a distinctive genus or species variety raised or maintained in cultivation, such as Euphorbia dulcis "Chameleon". Grex (Latin for "flock" or "herd") refers to a group of hybrids of common parentage, such as Lilium Pink Perfection Group. These concepts contributed a similar clarity to the nomenclature of garden or agricultural plants that Linnaeus had brought to the naming of native plants two centuries earlier. Stearn continued to play an active part in the International Botanical Congresses over many years, where he was remembered for his rhetorical persuasion on nomenclatural matters. He was also a pioneer in the application of computer-aided technology to (numerical taxonomy), as in his work on Columnea (1969). Botanical bibliography Motivated by his interest in botanical history and taxonomy, Stearn devoted a considerable part of his output to botanical bibliography, including numerous papers and catalogues establishing the exact publication dates of books on natural history, particularly from the early nineteenth century, including William Herbert's work on Amaryllidaceae (1821, 1837) and complete bibliographies of botanists such as John Gilmour (1989). At the RHS library he transformed the minimalist card indexing by introducing British Museum rules and adding extensive bibliographic information. He quickly realised that one of