This mutation was found by Ben Cecil in the crown of an old Ginkgo called Ben in the Bernhiem Arboretum in 2000. 
 
Description - Ginkgo biloba ‘Bernhiem Broom’ is a male dwarf form with slightly curling and notched, daintily small leaves only 4cm across, which are often closely overlapping. It has a strong branching habit. It is expected to develop into an irregular plant with a height and spread of approximately 3m.
 
Acknowledgement - Bindewald, Dr. M. 2020 for images of Ginkgo biloba 'Bernhiem Broom’