Professor Lorna Ann Casselton FRS (née Smith; born 18 July 1938, Rochford) is Emeritus Professor of Fungal Genetics in the Department of Plant Science at the University of Oxford, and is known for her genetic and molecular analysis of the mushroom Coprinus cinereus and Coprinus lagopus
The daughter of William Charles Henry Smith and Cecile Smith (née Bowman), she attended Southend High School for Girls. From University College London she gained a BSc and a PhD in 1964.
Casselton began her career in lecturing and research as an assistant lecturer at Royal Holloway College in London. She was Professor of Genetics at Queen Mary, University of London from 1989–91 and was later awarded an AFRC/BBSRC Postdoctoral Fellowship, followed by a BBSRC Senior Research Fellowship in 1995.
Professor Casselton was a Fellow of St Cross College Oxford from 1993–2003, and was appointed Professor of Fungal Genetics at Oxford in 1997. Her specialism is Sexual Development in Fungi. She was elected a Fellow of the Royal Society in 1999. She was a Fellow of St Cross College, Oxford from 1993 to 2003, and has been an Honorary Fellow of St Hilda's College, Oxford since 2000.