Knud Jessen

Knud Jessen (29 November 1884 – 14 April 1971) was a Danish botanist and quaternary geologist.

His scientific works mainly concern vegetation history during the Eemian interglacial, the late glacial period of the Wisconsin glaciation and in the Holocene investigated using pollen analysis.

[2] Jessen had come into contact with the Irish naturalist Robert Lloyd Praeger and made field-work on the quaternary geology of Ireland during 1934-1935.

Together with his assistant, Frank Mitchell, he was able to describe both the post-glacial vegetation development of Ireland and that of the Eemian interglacial, with the presence in Ireland of such plants as Rhododendron ponticum, Abies alba, Erica scoparia and Buxus sempervirens.

He was a member of the Royal Danish Academy of Sciences and Letters and served on the board of directors of the Carlsberg Foundation.