Rhododendron 'Madame Carvalho', which is a 1866 Waterer hybrid documented as R. catawbiense hybrid 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.
Rhododendron 'Madame Carvalho' is the seed parent of 'Gomer Waterer'. 'Pink Pearl' is the pollen parent of 'Gomer Waterer'.
Summary of Ploidy Levels
Diploid 'Madame Carvalho',
Triploid 'Gomer Waterer',
Triploid 'Pink Pearl'
Source: Van Veen Nursery
John and Sally Perkins
