The medal is awarded every four years for "outstanding contributions to lichenology" and this is only the second time the association's premier award has been made to a southern hemisphere lichenologist.
Dr Galloway (66), who has studied lichens for more than 40 years, was "absolutely chuffed" to receive the award in a ceremony at Knox College yesterday.
"I feel very, very happy but very humbled. I had no idea that this was in the wind."
Born in Invercargill, Dr Galloway is the author of more than 300 books and scientific papers on lichens and historical botany, including Flora of New Zealand Lichens, a two-volume work whose second edition was published last year.
He is an Honorary Research Associate of Landcare Research and former Professorial Research Fellow in the University of Otago biochemistry department.
Before returning to New Zealand in 1994, he had spent 22 years living in London, much of that time working at the Natural History Museum, where in 1976 he first met a visiting Swedish lichenologist, and now close friend, Prof Lars Arvidsson.
From 1987-92, Dr Galloway was president of the international association and and Prof Arvidsson was its secretary.
Prof Arvidsson presented Dr Galloway with the medal yesterday after a discussion on "Linnaeus: His Personality and Legacy".
Dr Galloway had spent quite a lot of time in Sweden working with Prof Arvidsson, who was "great fun".
"We work very well together," Dr Galloway said.
Dr Galloway is married to international opera singer Patricia Payne.
Carl Linnaeus (1707-78) was a Swedish botanist, physician and zoologist who is known as the father of modern taxonomy.
Swedish botanist Erik Acharius (1757-1819) was one of the last students of Linnaeus and is often hailed as the "father of lichenology."
