John Bretland Farmer was born at
Atherstone in
Warwickshire, the son of John Henry Farmer and his wife Elizabeth Corbett Bretland. He attended the Queen Elizabeth Grammar School in Atherstone. He won a place at
Magdalen College,
Oxford, graduating MA in 1887. During this period he was greatly influenced by
Isaac Bayley Balfour. He was made a Fellow of Magdalen College 1889–1897, demonstrator of botany in 1887–1892, and assistant professor of biology in 1892–1895 at Oxford, and then became
professor of botany at
Imperial College London. He received the
Doctor of Science (D.Sc.) from the University of Oxford in March 1902. He was appointed Governor of
The John Roan School and member of the council of
Hartley University College by the Senate of the University of London in January 1903. In 1892, he married Edith May Gertrude Pritchard, the daughter of
Charles Pritchard, Savilian professor of astronomy at the
University of Oxford. They had a daughter. ==Research and publications==