In 1922, he left Britain to take up a teaching role in the Danish-owned island of
St Croix (now part of the
US Virgin Islands). In 1923, he became professor of botany at the
Imperial College of Tropical Agriculture in
Trinidad and Tobago. In 1926, he also became director of the Cotton Research Station in Trinidad, continuing in this role until 1935. In 1940, he moved to
Peru as director of the Institute of Genetics within the National Agricultural Society of Peru. He returned to Britain in 1949 as a
reader in botany at the
University of Manchester, being made the George Harrison Professor of Botany at the University of Manchester the following year, 1950, and retaining this post until 1958, when he was subsequently made an emeritus professor. He was made a
Fellow of the Royal Society in 1943. In 1951, he was elected a Fellow of the
Royal Society of Edinburgh. His proposers were
Claude Wardlaw,
Herbert Graham Cannon, William Black and
William Robb. In 1952, a paper published by
Kathleen Basford on a cross-species of fuchsia which indicated the species had existed before the separation of landmasses 20-30 million years ago spurred him to offer her a job at the university. The two worked together at the university, including traveling to Peru together to breed maize. ==Personal life==