Rhododendron 'Mel's Rose', which is sometimes listed as a Rhododendron calendulaceum but is possibly a man made Rhododendron austrinum hybrid, has been determined to be a triploid 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
Triploid 'Mel's Rose',
Tetraploid Rhododendron austrinum,
Tetraploid Rhododendron calendulaceum
Source: John Thornton
John and Sally Perkins
