Career
He was the grandchild of the astronomer of same name. In 1783 Quensel became a student at the University of Lund and gained there (1787) his Magisterexamen in philosophy. In 1789 he undertook a study trip to Lappland, where he described several new species of insects.
Starting from 1791 he was an employee of the Botanic Garden at the University of Uppsala, in 1797 he became a Doctor of Medicine and after 1798 he became Director of the nature cabinet (Naturkabinetts) of the Royal Swedish Academy of Sciences in Stockholm.
Quensel wrote the largest part of the text of the first four volumes of the book " Svensk Botanik" (Swedish Botany) (1802–1843) with copper plates by Johan Wilhelm Palmstruch. He wrote also the text of the first volume of " Svensk Zoologi" in English SwedishZoology (1806–1809)and parts of Carl Johan Schönherr"s Genera et species curculionidum, cum synonymia hujus familiae,specie novae aut hactenus minus cognitae, descriptionibus a dom.
Leonardo Gyllenhal, C. H. Boheman. Et entomologis aliis illustratae.