Martyn was born in
London, the son of a merchant. He attended a school in the vicinity of his home, and when he turned 16, worked for his father, intending to follow a business career. He married Marie Anne Fonnereau, daughter of
Claude Fonnereau, a
Huguenot refugee who had settled in England and become a successful merchant. Martyn abandoned his business pursuits in favour of medical and botanical studies. His interest in botany came from his acquaintance with an apothecary, John Wilmer, and Dr.
Patrick Blair, a surgeon-apothecary from
Dundee who practiced in London. Martyn gave some botanical lectures in London in 1721 and 1726, and in 1727 was elected a Fellow of the
Royal Society of London. Martyn was one of the founders together with
Johann Jacob Dillenius and others, as well as the secretary of a botanical society which met for a few years in the
Rainbow coffee-house, Watling Street. An expanded version of this memoir was prepared and published by George Gorham in 1830. ==
Historia Plantarum Rariorum==