Horticulturist and botanist (1810-1878).
James McNab (25 April 1810 – 19 November 1878) was a British horticulturist, artist, and botanist. He was the son of William McNab (1780–1848) and the father of William Ramsay McNab (1844–1889). In 1848 he became curator of the Royal Botanic Garden Edinburgh, succeeding his father. He maintained careful notes on the flowering of plants in Edinburgh and foresaw possible changes in timing due to climatic changes.