Between 1785 and 1801 he published his Fasciculus plantarum cryptogamicarum Britanniae, a four-volume work in which he published over 400 species of algae and fungi that occur in the British Isles[1] He is also the editor of the exsiccata work Hortus siccus Britannicus, being a collection of dried British plants, named on the authority of the Linnean herbarium and other original collections (1793–1802).

[3] Dickson made several tours in the Scottish Highlands in search of plants between 1785 and 1791, that of 1789 being in company with Mungo Park, whose sister became his second wife.

He died at Broad Green, Croydon, Surrey, on 14 August 1822, his wife, a son, and two daughters surviving him.

[3] Sir Joseph Banks threw open his library to him, and he acquired a wide knowledge of botany, and especially of cryptogamic plants.

James Edward Smith wrote him an epitaph and Charles Louis L'Héritier de Brutelle dedicated to him the genus Dicksonia, among the tree-ferns.