James Alexander Macdonald FRSE FIB BSE (17 June 1908 – 26 April 1997) was a 20th-century Scottish botanist and plant pathologist.
He was born in Dingwall on 17 June 1908, one of five children, to Eliza Kelman and James Alexander Macdonald FRSE (1867–1937), HM Chief Inspector of Schools for the Scottish Highlands and a former rector of Leith Academy.
In the same year he became the joint founder and official keeper of St Andrews Botanic Garden.
In the Second World War he served as a flight lieutenant in the RAF in India and Malaya, mainly working in radar.
Although sickly in his early life, he developed a love of active sports by his late teens, including rugby and hockey.