Brownsey was born in
Wells, Somerset on 5 May 1948, to Margaret and John Derek Brownsey; his father worked as a banker. From 1959 to 1966 he attended
grammar school in
Crewkerne, Somerset, where he was inspired to study biology, later pursuing amateur natural history in the countryside of Somerset, Scotland, and Wales. Brownsey studied botany at the
University of Leeds under
Irene Manton, one of the rare female professors teaching there in the 1960s. The Botany Department at Leeds was strong in fern
systematics, and lecturers
Arthur Sledge and
John Lovis were both familiar with the New Zealand flora. Two of Brownsey's fellow graduate students were New Zealanders
Ross Beever and
Jessica Beever, and they encouraged him to consider working there. Shortly after completing his PhD thesis on European
Asplenium in 1973, Brownsey with his wife Wendy (whom he had married in 1971) moved to
Wellington to take up a post-doctoral fellowship at
Victoria University. == Research ==