German botanist who served as professor of botany at Oxford University. Johann Jacob (Jakob) Dillenius was born in Darmstadt and studied at Giessen, where his father (who latinized the family surname from Dillen to Dillenius) was a professor of medicine. Dillenius qualified in medicine and practised in Grünberg, Hesse and then as town doctor in Giessen. He meanwhile maintained an interest in botany, publishing several papers and the Catalogus plantarum sponte circa Gissam nascentium (1719), enumerating more than a thousand plants from the Giessen area along with his own illustrations.
With the encouragement of the botanist William Sherard, Dillenius moved to England in 1721 and became the first president of the Botanical Society of London. He was later appointed Sherardian Professor of Botany at Oxford, in 1734.
Dillenius published a third edition of John Ray's Synopsis Methodica Stirpium Britannicum in 1724 and in 1726 made a tour of Wales and western England with Littleton Brown (1699-1749), during which they collected plants, possibly in preparation for another edition of Ray's work. His next significant publication was a catalogue of the plants growing in the garden of Sherard's brother John at Eltham, London, entitled Hortus Elthamensis (1732), though he was not happy he had dedicated much time and money to the project.
Dillenius' major oeuvre was Historia muscorum (1741), which he had begun researching soon after he moved to England. Featuring 85 illustrated plates, it was one of the first botanical texts to refer to the work of Linnaeus. Dillenius met Linneaus in 1736 while he was in Oxford and the Swedish naturalist later dedicated his Critica botanica to Dillenius, as well as the genus Dillenia L. The pair exchanged a number of specimens.
After his death (from a stroke) Dillenius' collections of books, manuscripts, drawings and specimens were acquired by Oxford University.
Sources:
G.S. Boulger, rev. D.J. Mabberley, 2004, "Dillenius, Johann Jakob (1687-1747)", Oxford Dictionary of National Biography online edn:
www.oxforddnb.com/view/article/7648, accessed 14 November 2011
C. Jarvis, 2007, Order out of Chaos: 201.
