Rhododendron 'Orange Carpet', which is a natural hybrid collected in 1962 from Allatoona Lake, GA registered by Earl Sommerville documented as containing Rhododendron flammeum and Rhododendron calendulaceum, 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.
Based soley on the ploidy evidence, Rhododendron 'Orange Carpet' may not have Rhododendron calendulaceum in its parentage.
Summary of Ploidy Levels
Diploid Rhododendron flammeum,
Diploid Rhododendron 'Orange Carpet',
Tetraploid Rhododendron calendulaceum
Source: Planeview Nursery
John and Sally Perkins
