Rhododendron 'Duke Of York', which is a Paul hybrid documented as R. fortunei ssp. fortunei x 'Scipio', has been determined to be a diploid using flow cytometry by
Dr. João Loureiro, Dr. Silvia Castro, José Cerca, and Mariana Castro
Plant Ecology and Evolution Group,
Centre for Functional Ecology,
Department of Life Sciences,
Faculty of Science and Technology,
University of Coimbra, Portugal.
Summary of Ploidy Levels
Diploid 'Duke Of York'
Source: Arnold Arboretum Accession Number: 17601
John and Sally Perkins
