Rhododendron 'Lady De Rothchild', which is a 1925 Waterer hybrid documented as Rhododendron griffithianum x 'Sappho' has been determined to be a diploid using flow cytometry by
Dr. João Loureiro, Dr. Silvia Castro, José Cerca Oliveira, 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 'Lady De Rothchild'
Source: Whitney Nursery
John and Sally Perkins
