He was educated at Oundle School and Trinity College, Cambridge, where he read Natural Sciences, Music and History, receiving his degree in 1937.
Specializing, like Pearson, in agarics, Orton developed considerable expertise in identifying species and in 1955 received a Nuffield Foundation grant to work with Dr R.W.G.
The resulting New Checklist, published in 1960, was accompanied by 280 pages of descriptive and revisionary notes by Orton, including many new species.
In 1960 Orton took up a position at the newly opened Rannoch School in Perthshire, Scotland, where he taught biology, English, and music.
He also contributed, with Prof. Roy Watling, to the British Fungus Flora series, published by the Royal Botanic Garden, Edinburgh.