James MacFadyen (1799–1850) was a Scottish medical doctor and botanist who made a significant contribution to the scientific study of the plants of the Caribbean region.

[4] His developing medical career was curtailed by his application - on the recommendation of Sir William Hooker, at that time Professor of Botany at Glasgow University - to become "island botanist" with a brief to establish a botanical garden on Jamaica.

After his arrival there in August 1825, he embarked on a detailed study of its natural history, culminating in his two volumes of The Flora of Jamaica; the first was published at his own expense in Glasgow in 1837 and the second posthumously.

His attempt in 1825-26 to establish a botanical garden in the area around Bath was unsuccessful, caused by a combination of poor soil there and inadequate financial support.

He maintained contact with Sir William Hooker, who was later to become Director at Kew Gardens, by sending him accounts of his scientific studies and plant specimens over the period 1826-50.

[7] In letters to Sir William in 1849, Macfadyen complains about his inadequate “emoluments” that give him little time for botany and that prompt him to ask Hooker for help in securing alternative employment back in England.